Correct spelling, explanation: bury originates from the Germanic word burien. As is the case with many borrowings, the spelling changed to fit the English pronunciation and general word-formation rules. Considering that in English -en was not a suffix used for verbs, it disappeared, and i became y because of the pronunciation. The singular r stayed unchanged because it fit the pronunciation and did not disrupt any spelling rules in English.

Definition of bury:
verb
1. to put or store something underground
Grandma was buried in the nearest cemetery, and many people came to her funeral.
2. to hide or be obstructed under something
Kids buried my car keys underneath a mountain of toys.

Idioms with bury:
1. Bury the hatchet – to resolve or let go of a long conflict
My dad and his neighbor hated each other, but as I became friends with the neighbor’s kids they eventually buried the hatchet.
2. Dead and buried – long gone, no longer relevant (literally about a dead person or figuratively about something)
Let’s not talk about my relationship with him – it ended years ago, and at this point, it’s all dead and buried.

Incorrect spelling, explanation: if you’re unsure about the spelling of a word, usually thinking of related vocabulary may be helpful: in this case, you can think of burrial or burried, and notice that they are not quite right. Unfortunately, bury is not in any way related to a burrito, it comes from the Germanic word burien, and that’s why it’s spelled with only one r.