This is the 44th most frequent Estonian word.
lisas
The Estonian word "lisas" means "added" or "in addition."
In this context, 'lisas' indicates the action of adding or including something further, performed by 'ta' (she).
Peale õnnitlusi lisas ta kingituse.
After the congratulations, she added the gift.
In this sentence, 'lisasin' is the main verb in the past tense, meaning 'I added'.
Lisasin oma kirjale veel mõned täpsustused.
I added a few clarifications to my letter.
Here, 'lisas' functions as the main verb in the past tense, describing the action of adding something with the subject being the book.