This is the 285th most frequent Finnish word.
tuolloin
"Tuolloin" means "at that time" in English.
Here, 'tuolloin' specifies a particular, earlier time in the past referred to within the narrative, acting as a temporal adverb.
Tuolloin olin vielä opiskelija.
At that time, I was still a student.
In this sentence, 'tuolloin' references a specific past occasion, adding clarity and emphasis to the temporal context of the event.
Tapasimme ensimmäistä kertaa tuolloin.
We met for the first time at that time.
This use of 'tuolloin' establishes the timeframe of the statement, identifying it in the past and emphasizing its distinctiveness from the present.