"The cat loves my grandfather's armchair."
Translation:Le chat adore le fauteuil de mon grand-père.
"to like" = aimer/apprécier
"to love" = aimer if it's a person who loves another person or adorer if you are speaking about something else.
you have to remind that in French we have two "aimer", the one used for "to like" and the one used for "to love" and "aimer" (love), is stronger than adorer which is stronger than aimer (like) or appreciate.
Here it's a cat who loves an armchair, aimer (like) is not strong enough to be used, it's more used for "the cat likes the armchair" and aimer (love) is too strong to be used, it means "the cat is totally in love with the armchair" so you use the word between them : "adorer".
You may ask : how do you know if "J'aime Marie" means "I appreciate Marie" or "I love Marie"? We can't know, depends on the context. That may be why French people are so shy to say "Je t'aime" to their friends and family, they fear a bad interpretation ^^
There's a case where the language isn't enabling people to communicate the way they want and it may have other psychological effects which are subtle and depressing. I wonder if all languages have this kind of thing.
I could have sworn that possession/ownership of the armchair was denoted by "à" rather than "de". Am I wrong?
No!!! It's a very common mistake made by french people too^^ The possession is always denoted by "de" and "à" is a mistake. But in daily language you will hear "à" a lot and even if you are french and you no the rule, you will use "à" sometimes without paying attention...