こら

• (Tokyo) こら [kóꜜrà] (Atamadaka – [1])^[1]
• IPA^(key): [ko̞ɾa̠]

Possibly originally from 子等 (kora, “child”), an ancient term of endearment and address found in the Man'yōshū completed some time after 759 CE.^[2][1]

こら or コラ • (kora) 

1. hey (call of protest, call used to reprimand, scold, or admonish someone, especially a child)
   • 1927 December, Sasaki, Kuni, “苦心の学友 [Painstaking schoolmate]”, in 少年倶楽部 [Shōnen Club] (fiction), Kodansha:

     「こらこら、よけいなことをいわないで勉(べん)強(きょう)しろ」

     “korakora, yokei na koto o iwanai de benkyō shiro”

     "Come on, stop chattering and study!"

   • 1939, Eiji Yoshikawa, 宮本武蔵 空の巻 [Miyamoto Musashi, Book of Void]:

     「こらっ、童(わっぱ)ッ！　そんなところへ立(た)ってお客様(きゃくさま)のお居間(いま)をのぞいてはならん」

     “Kora', wappa'! Sonna tokoro e tatte okyakusama no o ima o nozoite wa naran”

     "Hey, child! Don't stand there to peak into the guest's room!"

2. hey (call of attention to someone)

• Stereotypically associated with yakuza and delinquents, often alongside おい (oi).

• ほら (hora)

The reading of kanji compounds.

こら • (kora) 

1. 子等, 児等: children; child (term of endearment or address)
2. 子良: in ancient times, an unmarried young woman working at Ise Shrine