One of the mysteries of the English language finally explained.
suffix
Forming nouns denoting female gender.
‘abbess’‘adulteress’‘tigress’
Usage
The suffix -ess has been used since the Middle Ages to form nouns denoting female persons, using a neutral or a male form as the base (such as hostess and actress from host and actor). Despite the apparent equivalence between the male and female pairs of forms, however, they are rarely equivalent in terms of actual use and connotation in modern English (consider the differences in meaning and use between manager and manageress). In the late 20th century, as the role of women in society changed, some of these feminine forms became problematic and are now regarded as old-fashioned, sexist, and patronizing (e.g., poetess, authoress, editress). The ‘male’ form is increasingly being used as the ‘neutral’ form, where the gender of the person concerned is simply unspecified
Origin
From French -esse, via late Latin from Greek -issa.
Pronunciation
suffix
Forming abstract nouns from adjectives, such as largess.
Origin
Middle English via French -esse from Latin -itia.