syntactically allowable part of a program that may be formed from one or more lexical tokens in accordance with the rules of the programming language, as defined by in the ISO/IEC 2382 standard (ISO/IEC JTC 1).[1] A term is defined as a “linguistic construct in a conceptual schema language that refers to an entity”.[1]
While the terms “language construct” and “control structure” are often used synonymously, there are additional types of logical constructs within a computer program, including variables, expressions, functions, or modules.
Control flow statements (such as conditionals, foreach loops, while loops, etc.) are language constructs, not functions. So while (true) is a language construct, while add(10) is a function call.
from: https://en.wikipedia.org/wiki/Language_construct
or better, from this discussion: https://stackoverflow.com/questions/23115462/what-is-the-meaning-of-construct-in-programming-languages
It’s a generic term that normally refers to some particular syntax included in the language to perform some task (like a loop with the condition at the end).