What is the meaning of Valuation?

An estimation of something's worth.

The process of estimating the value of a financial asset or liability.

An assignment of truth values to propositional variables, with a corresponding assignment of truth values to all propositional formulas with those variables (obtained through the recursive application of truth-valued functions corresponding to the logical connectives making up those formulas).

A structure, and the corresponding assignment of a truth value to each sentence in the language for that structure.

A measure of size or multiplicity.

A map from the class of open sets of a topological space to the set of positive real numbers including infinity.

Source: wiktionary.org