endo, exo, syn, anti

https://doi.org/10.1351/goldbook.E02094
Descriptors of the relative orientation of groups attached to non-@B00736-1@ atoms in a bicyclo[x.y.z]alkane (xy > z > 0).
E02094-1.png
If the group is orientated towards the highest numbered @B00736-2@ (z @B00736-2@, e.g. C-7 in example below) it is given the description exo; if it is orientated away from the highest numbered @B00736-2@ it is given the description endo. If the group is attached to the highest numbered @B00736-2@ and is orientated towards the lowest numbered @B00736-2@ (x @B00736-2@, e.g. C-2 in example below) it is given the description @S06216@; if the group is orientated away from the lowest numbered @B00736-2@ it is given the description @A00381@.
E02094-2.png
See also:
syn
,
anti
Source:
PAC, 1996, 68, 2193. (Basic terminology of stereochemistry (IUPAC Recommendations 1996)) on page 2207 [Terms] [Paper]