This is the 281st most frequent Slovenian word.
trije
"Trije" means "three" (masculine form) in English.
The word 'tri' in Slovenian is the numeral 'three', indicating quantity. It appears in its nominative form because it refers to objects in a plural form.
V trgovini sem kupil tri jabolka.
I bought three apples in the store.
The word 'tri' here is again the numeral 'three'. It is used to describe the quantity of 'friends', which is in the accusative plural.
Srečali smo tri prijatelje.
We met three friends.
'Tri' in this context represents a duration, referring to the number of hours (nominally feminine and plural in oblique cases) the action took.