This is the 7394th most frequent Japanese word.
会っ
"会っ" is the te-form of the verb "会う," meaning "to meet" or "to encounter."
会っ is used here in the past tense '会った', indicating that a meeting took place in the past.
昨日、学校で友達に会った。
I met my friend at school yesterday.
会っ is related to '会う', which in this sentence is used in the present tense form indicating a scheduled or planned upcoming meeting.
来週、先生と会う予定があります。
I plan to meet the teacher next week.
会っ is within '会っていない', showing the negative form of '会う', used to express not having met someone for a duration of time.