from The American Heritage® Dictionary of the English Language, 4th Edition
- pro. Informal Contraction of them.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- pro. Them (typically after a preposition, or otherwise with accusative or dative force; now only in unstressed position).
from the GNU version of the Collaborative International Dictionary of English
- An obsolete or colloquial contraction of the old form hem, them.
From Middle English hem, from Old English him, heom, dative and accusative pl. of hē, he; see he1.(American Heritage® Dictionary of the English Language, Fourth Edition)
Earlier hem, from Old English him, heom, originally a dative plural form but in Middle English coming to serve as an accusative plural as well. (Wiktionary)