Compounds having the structure $\ce{R2S(=O)=NR}$. (Indexed by Chemical Abstracts Service at the heading sulfoximines). E.g. $\ce{(CH3)2S(=O)=NPh}$ S,S-dimethyl-N-phenylsulfoximide.
Source: PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1370 [Terms] [Paper]