flor

Flor is feminine because it derives from Latin "flōs, flōris," which was a third-declension masculine noun in Latin. However, Spanish inherited it with feminine gender. The -or ending in Spanish typically indicates masculine nouns (e.g., "actor," "doctor"), but "flor" is an exception. The feminization likely occurred due to semantic association with other feminine nouns or phonetic patterns rather than a consistent gender rule. This makes "flor" an irregular case that must be learned as an exception.