You use this to give a reason. It means "since this is true, and for other reasons too." It helps you suggest something.
Clause + ことだしPrimary
You use this to give a reason. It means "since this is true, and for other reasons too." It helps you suggest something.
天気もいいことだし、公園に散歩に行こうか。
The weather's nice too, so shall we go for a walk in the park?
全員集まったことだし、そろそろ会議を始めましょう。
Since everyone has gathered, let's start the meeting soon.
特にお金もないことだし、今週末は家で映画でも見て過ごすよ。
I don't really have any money, so I'll just spend this weekend at home watching movies or something.
子供のことだし、少しぐらいの失敗は多めに見てあげてください。
He's just a child, so please be lenient about a few small mistakes.
A:「もう帰るの？」 B:「うん、明日も朝早いことだし。」
A: "You're leaving already?" B: "Yeah, since I have to get up early tomorrow morning (and for other reasons)."
This grammar is like saying 'since this is true, and maybe other things too.' It suggests there are more reasons, even if you don't say them. This makes your reason sound less strong, more like a friendly suggestion. It is not like 'because,' which gives only one reason.
This is different from '〜ことから'. That grammar explains why something is true. It is more formal. '〜ことだし' is for talking with people. It gives a reason for what you want to do. It is also different from 'から' and 'ので'. Those just give a reason. '〜ことだし' means there are other reasons too.
Don't use this when you write very formal things. For example, don't use it in a newspaper. Use it when you want to do something. Or when you suggest something. It is for talking about your own ideas. It is not for just stating facts.
Use this when you want to give a reason. This reason is something both you and the listener already know. It helps you suggest something or make a decision together.
Contrasts with(1)
Less formal alternatives(4)
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