This is the 341st most frequent French word.
devenu
"Devenu" means "become" in English.
'Devenu' is used here as the past participle of 'devenir' in the passé composé tense, agreeing with the subject 'je' (masculine singular).
Je suis devenu professeur après avoir étudié à l'université.
I became a teacher after studying at the university.
Here, 'devenu' describes a transformation in the subject (the tree) over time, in the past participle form used with 'être'.
L’arbre est devenu très grand au fil des ans.
The tree has become very tall over the years.
In this sentence, 'devenant' (present participle of 'devenir') is used to express the ongoing process of becoming.