What is the meaning of Niech?

forms third person imperative; let

forms the third person imperative in the singular and plural; let, may

forms the first person imperative in the singular; used only with perfective verbs; let, may

expresses optative meaning; had better, may

let (used to specify the meaning of a variable)

if only; only

expresses dissatisfaction or impatience

creates a subordinate clause expressing desire or wish; to, so that, for that, in order to

creates a conditional; if

Source: wiktionary.org