What does the logo of each Stack Exchange site represent?

Question

There are many sites on the SE Network that are based on different topics. From the question topics to the identity of each site's logo, what does it represent?

Answer 1

Many sites have a generic logo — a speech bubble in the SE brand color containing an abbreviation for the site. This speech bubble motif also continues in some of the custom logos.

Site	Logo	Site Topic	What the logo represents
Academia		academia	Books
Android Enthusiasts		Android	The Android logo, though slightly changed to look like a speech bubble
Anime & Manga		anime and manga	Based on the stylized kanji for 画
Arduino		Arduino	An infinity symbol, based on the Arduino community logo
Arqade		videogames and videogame consoles	The Iconic ship from the game Galaga
Artificial Intelligence		artificial intelligence	A fingerprint, possibly related to biometrics authentication, a common application of AI
Ask Different		Apple hardware or software	the Command key found on Mac keyboards
Ask Patents		finding Prior Art on dangerous and overly broad US Patent Applications before they become issued Patents
Ask Ubuntu		Ubuntu	A speech bubble in the Ubuntu primary brand color (co-designed by Canonical, the speech bubble was part of the design guidelines)
Aviation		aviation	An aircraft attitude indicator
Bicycles		bicycles and bicycling	A head tube badge
Biology		biology	A stylised DNA double-helix
Blender		blender	The logo of the Blender software, but slightly changed to look like a speech bubble
Bricks		LEGO bricks and compatible building systems	A 2x2 Lego brick, a very common piece that is in over 3,000 sets. Discussed here
Buddhism		Buddhist philosophy, teaching, and practice	A Dharmachakra or Wheel of Dharma
Chemistry		chemistry	A ball-and-stick diagram of Benzene
Chess		chess	a stylized illustration of a queen (one of the chess pieces)
Chinese Language		the Chinese language	「漢」 The first character of the name for the Chinese script「漢字」or Chinese language「漢語」
Christianity		Christianity	An encircled Western Christian cross
CiviCRM		CiviCRM	An adaptation of the CiviCRM logo
Code Golf		coding challenges and solutions	An award medal
Code Review		peer programmer code reviews	A magnifying glass looking at greeked code; the magnifying glass itself looks like a C and R, although some people see a Q, perhaps for “question” or “(code) quality”
Computer Science		computer science	a rooted binary tree
Constructed Languages		constructed languages	The ISO 639-5 code for constructed languages
Craft CMS		Craft CMS	The Craft CMS logo
Cross Validated		statistics	Inspired by k-fold cross-validation
Cryptography		cryptography and cryptanalysis	Other than the letter C, it has elements of Lock, Key, Vault, Puzzle
Database Administrators		databases	A UML-style symbol for a database
Drones and Model Aircraft		drones and model aircraft	UAV stands for Unmanned Aerial Vehicle, an alternate term for the subject
Drupal Answers		Drupal	A simplified Drupal logo
Electrical Engineering		electronics design	The circuit symbol for a diode
Emacs		Emacs	The letter e encapsulated in parentheses
English Language & Usage		English language and usage	A cursive (old-style) ampersand
English Language Learners		learning the English language	a bookmark
ExpressionEngine® Answers		ExpressionEngine	"... an icon mark, which reflect[s] the idea of a construction project: you always start with a plan or a schematic (the outlined E) of how something needs to be built. Then, as the project is finished, the final form (solid E) is what is seen by people for all time."
Game Development		game development	Three cubes
Geographic Information Systems		GIS	A compass
Graphic Design		graphic design	The logo represents the creation process of a logo itself, with sketch lines still being visible, circles, squares and triangles being the basic shapes of any graphic design
Hinduism		Hindu religion	Om
Home Improvement		home improvement	A cross-head screw
Information Security		Information security	The shield represents defense; “the lion […] symbolizes strength and valor; the wings represent swiftness and protection”
Islam		Islam	The Kaaba, a holy site in Islam
Japanese Language		the Japanese language	The first letter of the Japanese hiragana alphabet, which is the equivalent of the romanized letter A (meta post proposing it)
Magento		the Magento e-Commerce platform	"...logo which captures the essence of Magento's logo, but is still unique to the community."
MathOverflow		research level mathematics	A minimized version of the full logo, which consists of the name of the site with a visual indication of “overflow”
Mathematica		Mathematica	Inspired by Wolfram’s Mathematica logo, but modified due to copyright reasons
Mathematics		math	visually represents 6 cubes, whereas the design was made by Jin discussed from this meta post.
Meta Stack Exchange		the software that powers the Stack Exchange network	An empty Stack Exchange logo
Mi Yodeya		Judaism	Inspired by the Tree of Life, subtly includes the Star of David (a popular Jewish symbol), and a question mark (with the dot being the o of Yodeya)
Movies & TV		Movies and Television	Popcorn
Music: Practice & Theory		music practice, performance, composition, technique, theory, or history	Piano Keys
Network Engineering		network engineering	Symbol for a router
Personal Finance & Money		money or personal finance	A piggy-bank
Photography		photography	A Polaroid photograph
Physics		physics, astronomy and astrophysics	The "Mexican Hat" potential
Poker		poker	A club (card suit)
Puzzling		creating, solving, and studying puzzles	Lock + Impossible Geometry; “Lock” represents riddle, mystery, and discovery; “Impossible Geometry” represents complexity, (almost) impossible to solve, mathematics
Quantum Computing		quantum computing and quantum information	Logo with no discernible connection to quantum computing, adopted with no consultation with the community. (Possibly related to the logo of Strangeworks, the sponsor of the site.) Replacement proposals are being discussed.
Raspberry Pi		Raspberry Pi	Based on the Raspberry Pi logo; “Raspberry which symbolizes community roots and the device which is a foundation for everything you build [and] Circuit boards which are the main theme of the site”
Role-playing Games		role-playing games	a 20-sided die
Salesforce		anything Salesforce related	The Salesforce logo (a cloud with lots of connections inside)
Science Fiction & Fantasy		science fiction and fantasy	A rune circle
Seasoned Advice		food and cooking	A toque blanche (chef's white hat)
Server Fault		server, networking, or related infrastructure administration	There is no meta post associated with this logo, so presumably, it represents a server rack.
SharePoint		SharePoint	The nodes represent the six functions. The cube formed by the nodes and the connecting lines convey the idea that SharePoint is a whole service package. The flow bounded inside of the cube also forms an "S."
Signal Processing		the theory and applications of analog and digital signal processing, image processing and computer vision	A wave sign
Skeptics		challenging unreferenced notable claims, pseudoscience and biased results	Based on Wikipedia's [citation needed]
Software Engineering		software development	A cup of coffee. Essential part of every software engineer life.
Software Recommendations		detailed software recommendations for specific purposes	two symbols combined: a "cog (as a metaphor for software, tool, program or app) and compass (as a metaphor for guidance)"
Spanish Language		the Spanish language	the letter ñ, typically only found in Spanish
Stack Apps		apps, scripts, and development with the Stack Exchange API	A gear
スタック・オーバーフロー		プログラミング	See Stack Overflow
Stack Overflow em Português		programação	See Stack Overflow
Stack Overflow en español		programación, desarrollo y uso de software	See Stack Overflow
Stack Overflow на русском		программированию и системному администрированию	See Stack Overflow
Stack Overflow		programming	A stack of papers overflowing from an in-tray
Stellar		Stellar	The official currency code for the Stellar Lumen (see Tezos for reference)
Super User		computer software and hardware	an ASCII-style face.
TeX - LaTeX		TeX, LaTeX, ConTeXt, and related typesetting systems	A pair of braces, ubiquitous in the TeX world, represents a group, so the official logo {TEX} is a word play that means “TEX group”. The icon { } is a short form of that.
Tezos		Tezos	The official currency code of Tezos.
The Workplace		the workplace and other career-related topics	An origami letter O
Theoretical Computer Science		research-level questions in theoretical computer science	a deterministic finite automaton
Travel		travel-related questions	three overlapping pins as discussed in this meta post.
Unix & Linux		Linux, FreeBSD and other Un*x-like operating systems	U and L, short for Unix and Linux
User Experience		user experience	a combination of the two letters “UX” with a star in the middle created using negative space. The star signifies excellence, which is what the field of UX strives to achieve in product design.
Veganism & Vegetarianism		vegan and vegetarian lifestyle	The "suitable for vegans" symbol
Web Applications		web applications
Webmasters		the operation of websites
WordPress Development		theme and plugin development, development and management best practices and server configuration for WordPress	The WordPress logo
Worldbuilding		worldbuilding	An unfinished world represented by a primitive sphere; the coloring is taken from a scan of a brain during the act of imagining; the planetary ring was added to make it more distinguishable at smaller sizes
Writing		writing	A stylized pencil