This is the 118th most frequent Russian word.
свой
"Свой" means "one's own" or "possessing a connection to oneself."
In this sentence, "свой" refers to an item belonging to the subject of the sentence (I) and replaces the possessive pronoun "мой" (my). It is used to avoid repetition and conveys the same possession.
Я забыл свой кошелёк дома.
I forgot my wallet at home.
Here, "свой" indicates possession related to the person being addressed (you, in the plural or formal sense). It replaces "ваш" or "твой" (your) depending on the context and keeps the sentence fluent.
Не оставляйте свой велосипед без присмотра.
Don't leave your bicycle unattended.
In this case, "своём" refers back to the subject (everyone, in a general sense), ensuring the responsibility described is personal to each individual.