Flat, even, level, are all synonyms for smooth.
Smooth is an adjective. Smoothly is an adverb.
She touched his smooth face. - adjective. (describes the noun face)
They danced smoothly around the dance floor - adverb (gives more information about the verb dance)
even, soft, slick
flat
smooth endoplasmic reticulum
Flat can be a noun:I have a flat on my car.When used to modify another word, it is not a noun:I have a flat tire on my car.
bland, dull, flat, weak
The comparative of plain is 'plainer' and the superlative is 'plainest'.
Collapsed. Pancaked Crashed Toppled
The flat surface felt smooth.
Other words for 'flat' are... even, level smooth, equal.
Flat, even.
flat
A flat.
a platue
It means smooth, or flat
bumpy, rugh
buttery, soft, smooth
Tranquil, serene.
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smooth endoplasmic reticulum