It is not a currently defined term in Terminologia anatomica, though it has been used as a formal anatomical term in the past. The term "iliac furrow" does not appear in any of the abstracts indexed by PubMed. In modern usage, it is more common to discuss the surface anatomy in terms of nearby structures such as the inguinal ligament or iliac crest.
The term "iliac furrow" still often encountered when reading about art history, and the term "Apollo's belt" is often used by bodybuilders and their admirers. The expression "adonis belt" is also encountered, though less common, from the sense of adonis as any handsome young man (cf. the myth of Adonis).
An indentation on a male's waist caused by wearing a too-tight belt is often referred to as an Apollo's belt, although most men develop this indentation from constant waistband and belt pressure.