Origin and history of dam

c. 1200, "a mother," also "a woman of rank or high social position; superior of a convent," and an address for a woman of rank or position, used respectfully to other ladies, from Old French dame "lady, mistress, wife," from Late Latin domna, from Latin domina "lady, mistress of the house," from Latin domus "house" (from PIE root *dem- "house, household").

From early 14c. as "a woman" in general, particularly a mature or married woman or the mistress of a household. Used in Middle English with personifications (Study, Avarice, Fortune, Richesse, Nature, Misericordie). In later use the legal title for the wife of a knight or baronet.

Slang sense of "woman" in the broadest sense, without regard to rank or anything else, is attested by 1902 in American English.

We got sunlight on the sand

We got moonlight on the sea

We got mangoes and bananas

You can pick right off the tree

We got volleyball and ping-pong

And a lot of dandy games!

What ain't we got?

We ain't got dames! 

[Richard Rodgers, "There Is Nothin' Like a Dame," 1949]

principal city of the Netherlands; the name is a reference to the dam (see dam (n.1)) built on the Amstel river. The river name is said to be from Germanic elements ama "current" and stelle "place." Prevalence of dam in Dutch place names (Rotterdam, Edam, etc.) reflects the geography of Holland. In rhyming slang, "ram" (e.g. for one who "butts in" a queue).