Apostrophe for Compound Word Possessive
The Apostrophe
Rulebase Summary
Use an apostrophe and s on the last word of a compound word to show possession. The possessive marker goes on the final element of the compound, regardless of how many words or hyphens it contains.
Examples
A. My mother's-in-law house is across town.
A. My mother-in-law's house is across town.
The possessive marker goes on the last word of the compound — not on the first element.
A. The commander's-in-chief decision was final.
A. The commander-in-chief's decision was final.
Regardless of how many words or hyphens, the apostrophe and s attach to the final element.
Transcript Notes
Use an apostrophe and s on the LAST word of a compound word to show possession — even when the compound contains hyphens (mother-in-law's friend, sisters-in-law's friend, editor in chief's column, chief of police's car). The possessive is always added at the end of the entire compound, never to the head noun.
Style Guide References (1)
Morson's