A dog without an owner, living on the streets or in the wild.
There was a stray dog in the park.
野良犬 is a stray dog with no owner, the direct opposite of a 飼い犬, which belongs to someone.
Standard kanji spelling; the most common written form.
Search-only mixed kanji-kana form; not a standard spelling.
Compound of 野良 (のら, 'field' or 'wild') and 犬 (いぬ, 'dog'). The exact historical derivation is uncertain, but the word has been used to refer to ownerless dogs since at least the Edo period.