The singular is beau; the plural is either beaux or beaus.
singular beau (masc.) belle (fem.) plural beaux (masc.) belles (fem.) de beaux paysages - beautiful landscapes de belles voitures - beautiful cars
beau (plural 'beaux') is the masculine adjective meaning beautiful in French. The feminine form is 'belle'
Beaus or beaux is the plural of beau. Both are acceptable, although beaux is rather old-fashioned.
"Beautiful" in French is "beau" for masculine singular, "belle" for feminine singular, "beaux" for masculine plural, and "belles" for feminine plural.
The singular form of the demonstrative pronoun 'these' is this.
The singular form of "that" is "it."
The singular form of "cuffs" is cuff.
The singular form of "stratum" is "stratum." The word does not change in its singular form.
The singular form of feet is foot.
The singular form of diagnoses is diagnosis.
The singular form of scissors is "scissor."
The singular form of "oases" is "oasis."