This is the 635th most frequent Vietnamese word.
lâu
"Long" (in terms of time); "a long time."
The word 'lâu' is used to mean a long duration of time.
Tôi đã ở đây lâu rồi.
I have been here for a long time.
The word 'lâu' is used to signify a long period since the last meeting.
Lâu không gặp, bạn khỏe không?
Long time no see, how are you?
Although it sounds similar, in this case, 'lau' means 'to wipe' or 'to clean' in Vietnamese.