The Capricorn symbol (also called Capricorn glyph) is a shorthand representation of the Capricorn zodiac animal (see below). However, as with the animal itself, much is based both in interpretation and the preference of the writer, and can range from simple to extravagant.
Above are some examples of commonly used styles for the Capricorn symbol. Each of these is equally valid - there is no 'correct' version as long as the general shape is maintained.
Origins of the zodiac symbols and signs
The word 'Zodiac' means circle of animals (though note a couple of signs aren't animals in the normal sense). These 'animals' were based originally on the pattern of the stars in their corresponding star constellation. Basically what the earliest astronomers and astrologers saw when they squinted at the night sky.
Due to this although Capricorn will always be represented by a (sea)goat, there isn't any one 'correct' shape or design for that goat. It's a cosmic game of join the dots, and some constellations even have alternative ways to form the animal from the dots (stars).
Capricorn the goat
Any picture of the shape, head or profile of a goat can therefore be comfortably used here. Designs range from the space-age to the ancient, and are limited only by the imagination of the artist, as long as it gets the point across. In the case of Capricorn, just make sure it doesn't look like a ram, as that's the symbol of a different sign (Aries)
Below is a representation of Capricorn the goat (and the Capricorn symbol, inset) from a medieval wood carving from the 16th century. While it's not suggested this is a great picture (hey, you try carving something into the side of a tree which will look sexy in 400 years time!) it does show how the basic concept of Capricorn the goat hasn't changed much over the centuries.
We have a separate article on Capricorn tattoos