pho·to·pe·ri·od·ism 
(fō′tō-pîrē-ə-dĭz′əm)
(fō′tō-pîrē-ə-dĭz′əm)n.
An organism's response or ability to respond to changes in photoperiod.
- extorter
- extortion
- extortionary
- extortionate
- extortionately
- extortioner
- extortionist
- extortive
- extra
- extra-
- extra-base hit
- extracellular
- extracellularly
- extrachromosomal
- extracode
- extraconstitutional
- extracorporeal
- extracorporeally
- extracranial
- extract
- extractable
- extractible
- extraction
- extractive
- extractively