There are two accepted forms for possessive singular nouns that end with an s:
Add an apostrophe (') after the existing s at the end of the word:
Add an apostrophe s ('s) after the existing s at the end of the word:
possessive form of the word glass: glass'
The possessive form of the surname GLASS is GLASS's.
The possessive form for the singular noun glass is glass's (just as you have it in your question).The plural form is glasses. The plural possessive form is glasses'.Example: I like these glasses' pattern the best.
A bucket's contents.
The plural form for the noun glass is glasses. The plural possessive form is glasses'.Example: Her glasses' frame broke when she dropped them.
The plural possessive form is glasses'.
The possessive form of the noun folder is folder's.Example: This folder's label says '10 but the date of the contents are '01.
The singular possessive form is incinerator's.
The noun glass has a number of uses, all of them are uncountable nouns, except for a drinking glass. The plural possessive is glasses'; the set of glasses' color.The singular possessive for a pair of glassesused for eyesight is glasses', the glasses' frame. The plural possessive is the glasses' frames. The plural possessive is the same because it is a shortened form for the pairs of glasses' frames.The singular possessive for a pane of glass, used for windows is the glass's size. The plural possessive is the glass's sizes. The plural possessive is the same because it is a shortened form for the panes of glass's size.
The plural form of the singular noun diary is diaries.The plural possessive form is diaries'.example: The diaries' contents are the chronicles of my grandmother's travels.
The singular possessive form of the noun portfolio is portfolio's.example: The portfolio's contents indicate that the owner is a commercial artist.
The plural form is Bill of Rights.The plural possessive form is bill of rights'.Example:All members are required be familiar with our bill of rights' content.