1. Of the groin. (Google Dictionary)
2. In anatomy, the inguinal region is one of the regions of the abdomen, and the term inguinal refers to a structure belonging to this region. (medical-dictionary.thefreedictionary.com)
Word origin: From Latin inguinalis “of the groin,” from inguen “groin,” from PIE *engw– “groin, internal organ” (cf. Greek aden “gland”).