Balneum or balineum signifies, in its primary sense, a bath or bathing vessel, such as most Romans possessed in their own houses; and from that it came to mean the chamber which contained the bath. When the baths of private individuals became more sumptuous, and comprised many rooms, the plural balnea or balinea was adopted, which still, in correct language, had reference only to the baths of private persons. Balneae and balineae, which have no singular number, were the public baths. But this accuracy of diction is neglected by many of the subsequent writers. This image is Fresco from the Thermae of Titus. - Smith, 1873