Lewis & Short

balnĕŏlum, i, n. (plur. balnĕŏlae, ārum, f.), dim. [balneum], a small bath: balneolum angustum, tenebricosum, Sen. Ep. 86, 4; Juv. 7, 4: primus balneolas suspendit, Cic. Hortens. Fragm. 69 B. and K. (ap. Non. p. 194, 13); Aug. contra Ac. 3, 4.