1The basic expression of thanks, equivalent to 'thank you'. Etymologically a euphonic form of the adjective ありがたい ('precious / rare, hence appreciated'). Register and timing are distinguished by ending: ありがとう (casual, to peers or juniors), ありがとうございます (polite, for present/ongoing gratitude), ありがとうございました (polite, for a completed act), どうもありがとう / 本当にありがとう (emphatic). Casual shortenings include どうも and ありがと. One of the first essential phrases a Japanese learner picks up. Usually written in kana.
手伝ってくれてありがとう。
Thanks for helping me.
わざわざ来てくれて、本当にありがとう。
Thank you so much for going out of your way to come.
本日はお忙しい中、ご来場いただきありがとうございました。
Thank you very much for taking the time out of your busy day to attend today.
プレゼント、ありがと！すごく嬉しい。
Thanks for the present! I'm super happy.
「お先にどうぞ」「あ、どうもありがとうございます」
'Please, after you.' 'Oh, thank you very much.'