Attacking Agents in Organic reactions.

Every Organic reaction possess -
1.Reactant
2.Reagent
3.Solvent
5.Product
6. Leaving Group
Nucleophile is the species which attacks on positive charge or electron deficient center.
Electrophile is the species which attacks on Negative charge or electron rich center.
Ambiphile is the species which act as both Electrophile as well as Nucleophile.

Note - Following video Explains entire concept effectively