This is the 1326th most frequent Japanese word.
通っ
"通っ" is the continuative form of "通う" (kayu), meaning "to commute," "to go regularly," or "to pass through."
Here, '通っ' (as part of '通っています') is used to indicate habitual commuting or attendance to a place, in this case, a school.
彼は毎日学校に通っています。
He goes to school every day.
In this example, '通っ' (as part of '通っています') is used to denote the physical passage through a location, referencing the road extending across a city area.
この道路は市内を通っています。
This road passes through the city.
Here, '通っ' (as part of '通っている') implies a metaphorical passage or connection, in this case referring to the emotional understanding or communication.