lacu
lacu is a Latin form of lacus, meaning “lake, pond; tank, basin”. It is the ablative singular masculine noun.
Found 80 times in the Latin texts on Socratos.
Where it is used
Caesar, De Bello Gallico 1.2.3: … lvetium a Germanis dividit; altera ex parte monte Iura altissimo, qui est inter Sequanos et Helvetios; tertia lacu Lemanno et flumine Rhodano, qui provinciam nostram ab Helvetiis dividit.
Aulus Gellius, Noctes Atticae 11.15.1: LABERIUS in Lacu Averno mulierem amantem, verbo inusitatius ficto, amorabundam dixit.
All forms of lacus (declension table)
Source: Socratos (socratos.org), a free reader for Ancient Greek and Latin. Grammar from the Perseus Treebank and Morpheus; dictionary entries from Lewis & Short, A Latin Dictionary (Perseus Digital Library, CC BY-SA). Counts are from the texts on Socratos.