hieroglyph

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A picture or symbol used in hieroglyphic writing.
2. n. Something that suggests a hieroglyph.

Century Dictionary and Cyclopedia

1. n. The figure of any object, especially a familiar object, as an animal, tree, weapon, staff, etc., standing for a word, or a syllable, or a part of a syllable, or a single sound; a figure representing an idea; and intended to convey a meaning, thus forming part of a mode of written communication. The name was first applied to the engraved marks and symbols found on the monuments and other records of ancient Egypt. Of these, some signified directly the objects represented by them; others, conceptions suggested by those objects; others, ideas having names identical with or closely resembling the names of the objects represented; others, part of the sounds composing those names, or even only their initial sounds-these last being nearly a true alphabet, and used especially in writing proper names. The name, which had its origin in the idea that the sculptured symbols were exclusively sacerdotal, is now given to any writing of a similar character, as that of the ancient Mexicans, Peruvians, etc.
2. n. Any figure, character, or mark having or supposed to have a mysterious or enigmatical significance.
3. To write in hieroglyphs; represent by means of hieroglyphs.

Wiktionary

1. n. An element of an ideographic (hieroglyphic) writing system.

GNU Webster's 1913

1. n. A sacred character; a character used in picture writing, as of the ancient Egyptians, Mexicans, etc. Specifically, in the plural, the picture writing of the ancient Egyptian priests. It is made up of three, or, as some say, four classes of characters: first, the hieroglyphic proper, or figurative, in which the representation of the object conveys the idea of the object itself; second, the ideographic, consisting of symbols representing ideas, not sounds, as an ostrich feather is a symbol of truth; third, the phonetic, consisting of symbols employed as syllables of a word, or as letters of the alphabet, having a certain sound, as a hawk represented the vowel a.
2. n. colloq. Any character or figure which has, or is supposed to have, a hidden or mysterious significance; hence, any unintelligible or illegible character or mark.

WordNet 3.0

1. n. a writing system using picture symbols; used in ancient Egypt
2. n. writing that resembles hieroglyphics (usually by being illegible)