Sherry is a good example of how words can change when speakers misread their structure. The wine name ultimately comes from Jerez, the Spanish town name. In older English, forms such as sherris were common.
Once English speakers no longer recognized the original source, they treated the word as if it contained a plural ending. They then created a new singular form, sherry. This kind of change is called back formation or, more broadly here, reshaping by analogy.
Another influence may have helped: English speakers associated the sound with familiar fruit words, especially cherry or cherries. That made the new singular looking form feel natural.
- sherris: an older English form for the wine
- sherry: the later singular form that became standard
- pea from pease: another classic reanalysis
- cherry from Old French cherise: also reshaped in English
The key idea is simple: speakers often remake unfamiliar words into patterns they already know. Over time, the remade form can become the normal one.