This is the 56th most frequent Catalan word.
d
"D" is a contraction of "de," meaning "of" or "from" in English.
The word 'd' is a contraction of 'de' used before a name (Joan). It indicates possession.
La casa d'en Joan és gran.
Joan's house is big.
Here, 'd' is a contraction of 'de' used before a vowel (història). It modifies the noun 'llibre' to specify its type.
El llibre d'història és interessant.
The history book is interesting.
In this sentence, 'd' is a contraction of 'de' used to introduce the infinitive 'escriure', indicating purpose or intent.