spe·cial·ism 
(spĕshə-lĭz′əm)
(spĕshə-lĭz′əm)n.
1. Concentration of one's efforts in a given occupation or field of study.
2. A field of specialization.
- discussable
- discussant
- discussible
- discussion
- disdain
- disdainful
- disdainfully
- disdainfulness
- disease
- diseased
- disembark
- disembarkation
- disembarrass
- disembarrassment
- disembodiment
- disembody
- disembogue
- disemboguement
- disembowel
- disembowelment
- disemploy
- disemployment
- disempower
- disempowerment
- disenable