Borrowed from Middle High Germansöhn(“son”) (sȫne); cf. Sohn(“son”). The e is the nearest vowel to ö in Latvian; the length probably results from the influence of dēls(“son”). In an 18th-century dictionary, zēns is mentioned as “rarely used,” and only in the area around Riga and in Courland; in the 19th century, the word was still mostly used in Courland, but had already entered the literary language, as a synonym of puisis.[1]
zēnu istaba ― the boys' room (restroom, especially at school)
Haris ir zēns, viņam vēl tālu līdz lielam cilvēkam, viņš daudz nesaprot ― Haris is a boy, he has a long way to go to become a grown-up, he doesn't understand much
sanāca vairāk nekā divdesmit vīriešu, visvairāk jauni zēni, bet arī pusmūža vīri un pat pāris sirmgalvju ― more than twenty men came, mostly young boys, bet also some middle-aged men and a few seniors
es vēl negribu uzņemties rūpes par ģimeni... es esmu pavisam zaļš zēns ― I don't want to take care of the family yet... I am (still) a very green (= immature) boy
meitenei bija savs zēns ― the girl had a boy(friend)
no tās reizes, kad Jautrīte Raiņa vidusskolas sarīkojumā iepazinās ar Guntaru, daži sāka sačukstēties, ka Guntars esot Jautrītes zēns ― from that time when Jautrīte met Guntars at the event in the Rainis middle school, some (people) started to whisper that Guntars was Jautrīte's boy (= boyfriend)