Inseam/ˈɪnsiːm/ Definition 1 of 2Pro Tip 1/3Clothing Specific Inseam refers to a specific part of pants, not other clothing items. The dress's length is fine, but can you check the inseam on these jeans? Pro Tip 2/3Fit Importance The inseam affects how pants fit around the legs and crotch. These pants are tight; the inseam must be too short for me. Pro Tip 3/3Custom Tailoring Knowing your inseam is useful for having pants tailored to fit. The tailor adjusted the inseam for a perfect fit.