The English language Claymore is the original and official title to manga series in most languages, including Japanese.
Cover of the Russia edition adds Claymore above the transliterated Клеймор (prounounced clay-mor).
The Hong Kong edition adds 大劍 (pronounced da-Jee-an) above Claymore and is part of the copyrighted title.
Similarly, クレイモア (pronounced kray-mor) is added above Claymore on the Japanese cover, but is not part of the copyrighted title. クレイモア is a courtesy transliteration for Japanese-language readers only.
クレイモア does not appear on the copyright page of the Shueisha edition.
"Claymore" is not derived from クレイモア, but from the Scottish-Gaelic "claidheamh mór" (Great Sword), pronounced clave/glave-mor.
Tankōbon Claymore volumes cited are VIZ Media (en-us) editions, unless otherwise noted. Manga scenes (chapters) not yet translated cite Shueisha tankōbon (ja) editions. Manga scenes not yet published in tankōbon form cite Jump SQ (ja) editions. Fragments of Silver Omnibus (総集編 銀の断章 Gin no Danshou) 1–3, Shueisha, are only available in Japanese. Anime scenes (episodes) cited are FUNimation (en-us) editions, unless otherwise noted.