IPA: /sɪnˈθɛtɪkli/
KK: /sɪnˈθɛtɪkli/
In a way that involves the use of artificial substances or processes, rather than natural ones.
The chemicals were produced synthetically in the laboratory.
Synthetically → It is formed from "syn-" (meaning together) and "thesis" (from Greek "thesis", meaning placing or putting). The suffix "-ically" (meaning in a manner) indicates the manner of doing something. Thus, "synthetically" refers to doing something in a manner that combines or puts together elements.
Think of 'together' ('syn-') and 'placing' ('thesis') to remember that 'synthetically' means doing something by combining elements.