Entry 1 sense Webster, 1913 Roundhead /roun'-dhĕdˌ/ · Round·head · IPA /rˈaʊndhˌɛd/ 01 n. A nickname for a Puritan. See Roundheads, the, in the Dictionary of Noted Names in Fiction. 1. A nickname for a Puritan. See Roundheads, the, in the Dictionary of Noted Names in Fiction.(Eng. Hist.)