Is the French word 'art' a masculine or feminine noun?

Masculine is the gender of the French equivalent of the English Word "art."

Specifically, the French Word is "art." Its masculine singular definite article is "l"* ("the"). The pronunciation is "ahr."

*The article actually is "le." But the vowel "e" drops before a noun that begins with a vowel. The temporary nature of that drop is indicated by an apostrophe after the remaining letter "l" and immediately before the first letter of the succeeding Word.