Braintree, town (1990 pop. 33,836), E Mass., a suburb of Boston; inc. 1640. Metal, rubber, and paper are among its manufactures. Braintree included Quincy (birthplace of John Adams and John Quincy Adams) until 1792 and Randolph until 1793. John Hancock and Gen. Sylvanus Thayer, superintendent of West Point from 1817 to 1833, were born in Braintree. The Thayer Academy there was founded by the general.