Adjective
Of a land, suitable or allowable for constructing a building on.
Of a building or other thing, capable of being constructed.
(of a regular polygon) That can be constructed in a plane using only a pair of compasses and a straightedge.
(of a complex number) Such that the line segment joining it to the origin can be constructed using only a pair of compasses and a straightedge.
Source: en.wiktionary.orgA complex number is constructible if and only if the real and imaginary parts are both constructible. Source: Internet
A complex number is a constructible number if its corresponding point in the Euclidean plane is constructible from the usual x- and y-coordinate axes. Source: Internet
Gödel showed that the continuum hypothesis cannot be disproven from the axioms of Zermelo–Fraenkel set theory (with or without the axiom of choice), by developing the constructible universe of set theory in which the continuum hypothesis must hold. Source: Internet
All rational numbers are algebraic, and all constructible numbers are algebraic. Source: Internet
Also, if a and b are constructible numbers with b ≠ 0, then and a − b are constructible. Source: Internet
Geometric definitions The geometric definition of a constructible point is as follows. Source: Internet