The definite form (noteiktā galotne) points to a specific, already known thing — much like the English definite article ‘the’.
Masculine definite adjectives end in -ais, feminine in -ā.
Examples
jaunais
the new one (m.)
jaunā
the new one (f.)
The definite form is also used:
with the superlative degree
vis-lab-ais — the best
after demonstrative pronouns
tas jaunais — that new one
in names and titles
Vecrīga, Baltais nams
for ordinal numbers
pirmais — the first
Man patīk jaunā māja.
I like the new house.