from The American Heritage® Dictionary of the English Language, 4th Edition
- interj. Used to attract attention or to express surprise, appreciation, wonder, or pleasure.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- interj. An exclamation to get attention.
- interj. A protest or reprimand.
- interj. An expression of surprise.
- interj. An informal greeting, similar to hi (used in the US, Australia and Canada).
- interj. A request for repetition or explanation; an expression of confusion (see also eh, huh).
- interj. A meaningless beat marker or extra, filler syllable in musical lyrics.
- n. A choreographic figure in which the dancers weave between one another.
from the GNU version of the Collaborative International Dictionary of English
- adj. High.
- interj. An exclamation of joy, surprise, or encouragement.
- interj. A cry to set dogs on.
from The Century Dictionary and Cyclopedia
- An exclamation expressing pleasure, surprise, etc.: also used as a call to attract attention and as an interrogative.
- An obsolete form of high.
- n. An obsolete form of hie.
- n. An obsolete or rare form of hay.
From Middle English hey, hei, also without h- in ey, from Old English *hē, ēa (interjection), attested as first element in Old English hēlā, ēalā ("O!, alas!, oh!, lo!"). Cognate with Dutch he, hei ("hi, hey"), German hei ("hey, wow"), Danish and Swedish hej ("hello, hey"), Faroese hey ("hey, hello"), Icelandic hei ("hey"), see heigh. Probably a natural expression, as may be inferred from its presence with similar meaning in many other unrelated languages: for example, Burmese ဟေး (hei), Finnish hei, Unami hè, and Mandarin Chinese 哎 (āi), and various sound-alikes as Roman eho, Greek εἴα (eia), Latin eia. See also hello. (Wiktionary)