The verb "to tackle" has two main meanings. In team sports, it means to stop an opposing player by physical force. It means to collide with them, wrestle with them, knock or pull them down to the ground.
Figuratively, it means to fight, struggle, or wrestle with a difficult problem.
"Jane Austen's novels are in difficult English. I don't think you're ready to tackle them."
As a noun, it can certain kinds of equipment. It is a rough synonym for "gear." However, it is used only in certain contexts. Equipment for fishing is your "fishing tackle." On a ship, a system of ropes and pulleys for lifting heavy loads is "a block and tackle."