expression, godan verb (-ku)
consult a dictionary; look up in a dictionary
Standard expression for looking up a word or meaning in a dictionary. The verb 引く here means 'to pull' or 'to draw', metaphorically pulling information from the dictionary.
知らない単語があったら、すぐ辞書を引いてください。
If you come across a word you don't know, please look it up in a dictionary right away.
彼は毎日、
He studies every day by consulting an English-Japanese dictionary.