mann-
combining form 
or manno-
Etymology: International Scientific Vocabulary, from manna 
1. : manna 
< mannite >
< mannose >
2. : related to mannose 
< mannan >
3. manno-, usually italic : having the stereochemical arrangement of atoms or groups found in mannose 
< d-manno-3-hexulose >
< manno-saccharic acid >
or manno-
1.
< mannite >
< mannose >
2.
< mannan >
3. manno-, usually italic
< d-manno-3-hexulose >
< manno-saccharic acid >