Latest means most recent of all. The one that came out last, and nothing newer exists yet.
It is the superlative of late in its recent sense, and it always implies a series, so the latest album is one of several. Take care with the difference from last, since the last book means the final one and the latest book means the newest so far. There is a fixed phrase, at the latest, which sets a deadline: Friday at the latest. Asking what's the latest means asking for news.
1adjectivelatestMost recent.
“Have you heard her latest song?”
Old English
latost
Middle English
lateste
English, today
latest
From Middle English lateste, from Old English latost, latest, lætest, superlative of læt, whence English late. a doublet of last.
Etymology from Wiktionary, CC BY-SA