(mōst) adjective
1. Consisting of the greatest number: superlative of many.
2. Consisting of the greatest amount or quantity: superlative of much.
3. Obs. Greatest in size, rank, or age.
—noun
1. The greater number; the larger part: the most of my belongings.
2. Greatest amount, value, or advantage; utmost degree, extent, or effect.
—adverb
1. In the highest degree, or in the greatest number or quantity.
2. Dial. Almost.
3. Greatest, as in amount or degree: used with adjectives and adverbs to form the superlative degree. [OE mæst]

Most: added to adjectives, adverbs, and prepositions to form superlatives: outmost. [OE -mest <-ma + -est, superlative suffixes]