– Encyclopedia of Symbols

This is an encyclopedia of symbols, signs, flags and glyphs. It contains background articles and dozens of symbol groups, from astronomy and astrology to weather and wingdings. The search feature works best when you know the word for the symbol. Typing the symbol in the search box
(such as Ω) did not produce usable results. But the index by theme is easy to navigate if you know the category for a symbol, such as mathematic, medical, or even hobo signs.