This is the 15527th most frequent Russian word.
преподавал
"Taught."
The word "преподавал" is used in its past tense form to indicate that the subject, "he," taught something, specifically Russian language at the university, in the past.
Он преподавал русский язык в университете.
He taught Russian at the university.
Here, "преподавала" is the past tense feminine form of the verb, showing that the subject performed the action of teaching mathematics at a school in the past.
Она преподавала математику в школе в течение пяти лет.
She taught mathematics at a school for five years.
In this instance, "преподавал" reflects the past tense first-person singular form, depicting the act of teaching English to students with a beginner level of proficiency.