smallest
adj.adj. the most tiny or little in size compared to everything else in a group. You use this when nothing else is smaller than the thing you are talking about.
adj. the superlative form of small, indicating the least possible size, amount, or degree within a specific set.
The smallest kitten in the group is very quiet.
We need to find the smallest box in the warehouse to pack this tiny piece of jewelry.
Even the smallest error in the initial calculations can lead to a significant discrepancy in the final structural integrity of the bridge.
As a superlative adjective, it is almost always preceded by the definite article 'the'.
the most smallestthe smallestSmall is a one-syllable adjective, so it takes the '-est' ending; using 'most' with it is grammatically incorrect.