ことだし
(And) so, Because, Since
Structure
［い］Adjective + ことだし
［な］Adjective + な(1) + ことだし
Noun + の(1) + ことだし
(1) である
Explanation
ことだし is composed of the noun こと, the copula だ, and the particle し, which is used to list multiple items. This grammar pattern presents one particular reason for something, implying that other reasons also exist. It generally translates to 'since (A)' or 'given that (A)', but with the added nuance that the speaker has more reasons in mind than just the one they are mentioning.
This structure can be attached to any word that is in its attributive form, or it can be used after a noun that is followed by の.
- あそこのお店、セールをやってることだし、今日のうちに買い物に行っておこう。Since that store over there is having a sale, let's go get our shopping done today.
- まだ時間も早いことだし、もう一軒どこかに寄って帰らない？Since it's still early, why don't we stop by one more place on our way home?
- 明日は二人とも暇なことだし、映画でも見にいかない？Given that we're both free tomorrow, why don't we go see a movie or something?
- 田中さんのことだし、きっと時間どおりに来るはずだよ。Knowing Tanaka-san, I'm sure she'll be here right on time.
The particle し retains its original function of implying a non-exhaustive list. In this structure, it signals that the stated reason (A) is just one of several, but is sufficient on its own to justify the following conclusion (B). The clause that follows (B) often contains a suggestion, an invitation, or a statement of the speaker's intent.
Examples
このレストランは料理もおいしいことだし、雰囲気もいいから今度のデートはここにしよう。
Since the food at this restaurant is delicious and the atmosphere is nice, let's have our next date here.
時間もたくさんあることだし、急がないでゆっくり話そうか。
We have plenty of time, so shall we talk slowly without rushing?
雨も降り出したことだし、洗濯物を取り込まないと。
It's started to rain, so I have to bring in the laundry.
みんな疲れていることだし、今日は早めに仕事を切り上げて帰ったらどう？
Since everyone is tired, how about we finish up work early and go home for the day?
頑張り屋の田中さんのことだし、この難しいプロジェクトもきっと成功させるでしょう。
Knowing the hard-working Tanaka-san, I'm sure he'll make this difficult project a success.
彼も一生懸命練習していることだし、少しくらい応援してあげようよ。
He's practicing with all his might, so let's at least cheer him on a little.
明日は休みだ。それに、給料日だったことだし、今夜はパーッと飲みに行きたいな。
Tomorrow's a day off. Plus, I just got paid today, so I feel like going out for a big night of drinking.
この辺は静かなことだし、引っ越すならここにしようと思っている。
This area is quiet, so I'm thinking of moving here if I'm going to move.
社長が社員に：「皆さんも賛成していることだし、この新しい方針で進めてはどうだろうか。」
The company president to the employees: 'Since all of you are in favor, how about we proceed with this new policy?'
彼はまだ新人なことだし、少しくらいのミスは仕方がないよ。
Since he's still a newcomer, a few mistakes can't be helped.
欲しかったゲームが発売されたことだし、週末は一日中やり込むぞ！
Since the game I wanted was just released, I'm going to play it all day this weekend!
天気もいいことだし、近くの公園まで散歩にでも行こうかな〜。
Since the weather is nice, I wonder if I should go for a walk to a nearby park or something.