Usually a Gohma is a spider enemy in Zelda games. Their usual weakness is in the eye, and they tend to use claws or their legs to inflict damage. And they move fast from side to side like a crab. Though they move slow when going forward or backward.
Armogohma came from what the others have said, Armo coming from armor, a thick plating used to protect the wearer from a certain amount of damage. The Gohma meaning a spider or the enemy of Zelda games.
OoT and TP had their own version of Gohma, and there are many varieties of Gohma's. But all have the same weaknesses and strengths like any other Gohma, Their eyes and their limbs.