tavolo

There is no -ol- suffix in Esperanto. Not a rare one, not a semi-official one: it does not exist. The official list has -obl- (multiples: duobla, double), -on- (fractions: duono, half) and -op- (groups: duope, in twos), and a learner scanning tavolo for a suffix will find -ol- sitting in the gap between two of them. Nothing is there. Tavol- is one root, and the best defence against inventing suffixes is knowing how short the real list is: twenty-eight of them, and you can read the whole thing in a minute.

What it means, precisely. A tavolo is a stratum: material spread flat and lying on top of other material. Snow on a field, paint on a wall, sponge in a cake, rock under sand. The verb tavoligi is to arrange in layers, tavoliĝi is to settle into them, and sentavola is uniform all the way through.

Against the three words it keeps getting confused with.Nivelo is a height, a position on a scale - it has no thickness and no substance, so water reaches a nivelo but is not one. Grado is a degree, a step on a graded scale of intensity. Ŝtupo is a step you can stand on, literal or figurative. Tavolo is the only one of the four that is made of stuff.