This is the 97th most frequent Hebrew word.
היתה
"Was" (feminine singular).
In this sentence, 'הייתה' (haita) is a form of the verb 'to be' in the past tense, referring to a singular feminine subject.
היא הייתה בבית הספר אתמול.
She was at school yesterday.
In this sentence, 'הייתה' (haita) describes the existence of 'an important team meeting' in the past.
הגעתי מוקדם כי הייתה פגישת צוות חשובה.
I arrived early because there was an important team meeting.
Here, 'הייתה' (haita) is used impersonally to denote the existence of 'a time' in past tense, acting similarly to 'there was' in English.