でも

で (de, conjunctive ("て-form") of copula だ/です) +‎ も (mo, “even; too”).^[1]

When でも follows a noun, で is the conjunctive or "て-form" of the copula だ/です. で can also appear in the conjunctive form of certain classes of verbs; in that case, でも can be analyzed as the conjunctive form of the verb + the inclusive particle も, and means "even if"; compare with the allomorph ても used for different classes of verbs.

• (Tokyo) でも [déꜜ mò] (Atamadaka – [1]) (conjunction)
• IPA^(key): [de̞ mo̞]

でも • (de mo) 

1. even

   先生(せんせい)でも間違(まちが)えるよ。

   Sensei demo Machigaeru yo.

   Even teachers make mistakes.

2. or

   お茶(ちゃ)でも、コーヒーでも、どうですか？

   O-cha de mo, kōhī de mo, dō desu ka?

   How about some tea or coffee?

3. or something

   酒(さけ)でも飲(の)もうよ。

   Sake de mo nomō yo.

   Let's have a drink or something.

   気(き)づかないとでも思(おも)った？

   Kizukanai to de mo omotta?

   Did you think I wouldn't notice or something?

   気(き)づかないとでも？

   Kizukanai to de mo?

   [Did you think] I wouldn't notice or something?

   • 1948, Osamu Dazai, Ningen Shikkaku [No Longer Human]‎^[1]:

     毛(け)虫(むし)でも払(はら)いのける時(とき)のような手(て)つきで

     kemushi de mo harainokeru toki no yō na tetsuki de

     with a hand movement as if one were brushing away a caterpillar or the like

でも • (de mo) 

1. (informal) but, however

   でも、私(わたし)はそう思(おも)わない。

   De mo, watashi wa sō omowanai.

   But I don't think so.

• (but): ただし (tadashi)

で (de, “at; in”) +‎ も (mo, “even; too”)

1. also in

   日(に)本(ほん)でも英(えい)語(ご)を勉(べん)強(きょう)する。

   Nihon de mo eigo o benkyō suru.

   In Japan also, we study English.

   宇(う)宙(ちゅう)からでも万(ばん)里(り)の長(ちょう)城(じょう)が見(み)える。

   Uchū kara de mo Banri no Chōjō ga mieru.

   Even from space you can see the Great Wall of China.

(This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium.)

でも • (de mo) 

1. (after interrogatives) any, without restriction

   食(しょく)事(じ)制(せい)限(げん)はないので何(なん)でも大丈夫(だいじょうぶ)です。

   Shokujiseigen wa nainode Nan de mo Daijōbudesu .

   I don't have any dietary restrictions so anything is fine.

   この仕事(しごと)は(は)誰(だれ)でもいい

   kono Shigoto wa Dare demo ī

   Anybody will do for this work

(compare with か and も, which express the indefinite pronouns "some" (something, someone) and "all"/"none", respectively, when used after interrogatives)