SEAMLESS definition: 1. without any seams (= lines of sewing joining different pieces of cloth): 2. happening without…. Learn more. Seamless means without a seam or with no spaces or breaks between one part and the next. Learn how to use this adjective with pictures, pronunciation and usage notes. seamless definition: smooth and without any interruptions or inconsistencies. Check meanings, examples, usage tips, pronunciation, domains, and related words. Discover expressions like "make a seamless whole", "seamless process", "seamless transition". SEAMLESS meaning: 1 : having no seams; 2 : moving from one thing to another easily and without any interruptions or problems