We don't have synonyms for backstitch yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are lockstitch, backstretch and backstick.
(n) :
(sewing) A type of sewing stitch where the stitch goes backwards on the top side of the fabric and doubles forward on the bottom, coming out farther in front, then repeats. The backstitch is a very tight and secure stitch, and also looks very neat.
(n) :
(sewing) A type of sewing stitch where the stitch goes backwards on the top side of the fabric and doubles forward on the bottom, coming out farther in front, then repeats. The backstitch is a very tight and secure stitch, and also looks very neat.