Denshi Jisho — Online Japanese dictionary

或る ある a certain ...; some ...
Pre-noun adjectival, Usually written using kana alone 
或る日 あるひ one day (e.g. "one day while studying, ..")
Noun 
或る種 あるしゅ certain; some kind of; some sort of; of sorts
No-adjective 
或る時 あるとき once (i.e. "once, when I was studying ..")
Noun 
或る人 あるひと someone (unspecified, but someone in particular); a certain person
Noun 
或る程度 あるていど to some extent; to a certain extent
Expression, No-adjective, Adverb 
或る程度まで あるていどまで to some degree; up to a point; to some extent
Expression 

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