tacking       
noun [ U ]  fabrics uk/ˈtæk.ɪŋ/ us/ˈtæk.ɪŋ/ (also mainly US basting)
 (将两块布料临时缝在一起的)松散的长针脚
long, loose stitches that are used to hold two pieces of cloth together temporarily before they are sewn together in a neater and permanent way
  Remove the tacking. 把松散的长针脚拆掉。 
 Suits are typically sold with tacking stitches holding the vent at the back of the jacket in place. 西服出售的时候,通常会用松散的长针脚把外套背后的开衩缝起来。 
 See: tack
 - More examples
 - Machine the seam from the wrong side over the tacking.
 - Then take out the tacking stitches and remove the card and you should have a really spectacular garment.
 - She unfastened the tacking of one long satin sleeve of Flora's wedding gown and began to re-pin it.