Headache
The compound word for school head is headmaster.
Yes, masthead is a compound word, as both "mast" and "head" are words.
The examples provided are not compound words.
blackheadblockheadbulkheadheadbandheadgearheadlightheadlineheadphoneswhitehead
arrowheadbeachheadblockheadbullheadbulkheadfigureheadforeheadheadbandheadbangerheadline, headlinerpinheadwhiteheadblackheadheadmasterhammerheadheadphonesheadgearheadpinheadstrongtowheadmastheadtowheadwellhead
headache
overhead
yes , because head is a word and ache is a word
line
The word head makes a compound word with both arrow and line. Examples: arrowhead, headline
Both "arrow" and "line" can combine with "head" to make a compound word. arrowhead headline
light