Lam
A surname with several possible origins, most often linked to a short form of personal names or to Chinese and other East Asian surnames.
The #611 most common surname in the United States (2010 Census) — about 1 in every 5,558 Americans shares it.
Etymology
The surname Lam is not a single clear-cut English name. In English records, it can appear as a shortened or altered form connected with personal names such as Lambert, or as part of compounds that older writers struggled to explain. Separately, Lam is also a well-known surname in several Asian naming traditions, where it may represent different original characters or words that are unrelated to the English surname.
History
Older surname dictionaries treat Lam cautiously, and some English examples seem to be spelling reductions or later corruptions rather than a stable medieval surname. In modern use, however, Lam is especially common as a family name among people of Chinese, Vietnamese, and other East Asian backgrounds, which is why the name is now widespread well beyond its older English contexts. Because the same spelling can arise from different languages, bearers of the surname may have entirely different family histories.
Origin
Regions
Variant spellings
Fun fact
In English onomastics, older writers sometimes treated Lam as a reduced form of longer names, while in contemporary global usage it is far more often an East Asian surname.
From the historical record
“D'Allemagne] LAM BEL (Fr.) a double dim. of Lambert, q.v. in Diet [Fr. dim. suff. -el, Lat. -ell-us] LANDEAU 1 (Fr.) double dims, of Roland, LANDEL ..'q.v. in Diet. [Fr. dim. suft. -^aM, earlier -el, Lat. -ell-us\ LANGE (Fr.) The Angel [Fr. £', the; Lat. ille + ange, angel : see Angel(l in Diet. (Ger.) Long, Tall…”
— Surnames of the United Kingdom: a concise etymological dictionary (2 vols in 1)