themer

noun

1. One who themes something.
2. One who themes something.

   “This structure organizes and streamlines theme development to create a solid ground for themers (theme developers) to further build and extend, much like in object-oriented programming.”

3. An entry in a crossword that forms part of the theme.

   “The first of the themers is SPARRING PARTNER (“Opponent who helps train a boxer”) — which, as the revealer indicates, includes the word PAR twice.”

   “I threw in a bonus with ASTHMA – Longest familiar word in the English language that begins and ends with a vowel with no vowels in between (though you may not want to use that clue since there is no symmetrical themer).”

   “One themer that ended up on the cutting room floor here is HEADSPACE, a word I find myself using pretty often (e.g. "I'm not in the right HEADSPACE for that right now").”