from The American Heritage® Dictionary of the English Language, 4th Edition
- Is: She's here.
- Has: He's arrived.
- Does: What's he want?
- Us: Let's go.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- v. contracted form of is
- v. contracted form of has
- v. contracted form of does (used only with the auxiliary meaning of does and only after interrogative words)
- v. are
- pro. Contracted form of us found in the formula let’s used to form first-person plural imperatives. Let’s is now considered as a compound.
- pro. Contracted form of as in its nonstandard use as a relative pronoun.
- prep. Possessive marker, indicating than an object belongs to the noun phrase bearing the marker.
- prep. In the absence of a specified object, used to indicate “the house/place/establishment of”.
- suffix Indicates a purpose or a user.
- suffix Used to form the plurals of numerals, letters, some abbreviations and some nouns, usually because the omission of an apostrophe would make the meaning unclear or ambiguous.
- suffix Used to form the plural of nouns that correctly take just an "s" in the plural. See greengrocer’s apostrophe.
from the GNU version of the Collaborative International Dictionary of English
- A contraction for is or (colloquially) for has.
Representing the Old English masculine and neuter genitive singular ending -es. (Wiktionary)
Equivalent to -s, with arbitrary use of apostrophe. (Wiktionary)