From Longman Dictionary of Contemporary Englishpinheadpin‧head /ˈpɪnhed/ noun [countable] Dthe small round part at one end of a pin
Examples from the Corpus
pinhead• Use morning and/or night and dot a pinhead amount underneath and around the outside edge.• Grains the size of a pinhead are ideal.• The computer will ultimately collapse to a pinhead that can respond tO the human vOice.• It triggered an image of a diver shooting to the surface with a pinhead of breath, his arm like Excalibur.• Only that pinhead J. D. Hayworth has remained a loyal lackey.• I have to deal with pinheads like him all day at work. 