According to the docstring of define-abbrev
:
- `:case-fixed': non-nil means that abbreviations are looked up without case-folding, and the expansion is not capitalized/upcased.
To disable case folding, set :case-fixed
to true on the abbrev tables you use:
(abbrev-table-put global-abbrev-table :case-fixed t)
Or, to do it for all abbrev tables:
(dolist (tbl abbrev-table-name-list)
(abbrev-table-put tbl :case-fixed t))