This is the 2792nd most frequent Japanese word.
過
"過" means "past," "over," or "exceed."
過去 - In this context, '過' is part of the word '過去', which refers to 'the past', indicating a timeframe that has already occurred.
昨日、図書館で過去の書籍を読みました。
Yesterday, I read books from the past in the library.
飲み過ぎ - Here, '過' is used in the verb-compound '飲み過ぎ', meaning 'to overdrink'. It signifies excessiveness when combined with verbs.
ランニングの後で、水を飲み過ぎてしまいました。
After running, I drank too much water.
過ぎる - '過' here appears in the verb '過ぎる', which means 'to pass'. It denotes movement past a specific location.