1notch 
/ˈnɑ:tʃ/ noun
plural notch·es /ˈnɑ:tʃ/ noun [count] 1 : a small cut that is shaped like a V and that is made on an edge or a surface
▪ Cut small notches at the corners of the fabric. ▪ The tool has a notch for prying out nails. 2 US : a narrow passage between mountains
▪ The town is on the other side of the notch. 3 : a slightly higher or lower level in a series of levels that measure something
▪ Turn the radio up/down a notch. [=up/down slightly] ▪ They turned the volume up several notches. ▪ This product is a notch [=step] above its competitors in quality and price. — see also top-notch
▪ Cut small notches at the corners of the fabric. ▪ The tool has a notch for prying out nails.
▪ The town is on the other side of the notch.
▪ Turn the radio up/down a notch. [=up/down slightly] ▪ They turned the volume up several notches. ▪ This product is a notch [=step] above its competitors in quality and price. — see also top-notch
