Atoms & structure
Proton — প্রোটন
Quick answer
A proton is a positively charged particle in the nucleus; its count is the atomic number.
Definition
A proton is a heavy particle carrying one unit of positive charge, sitting in the nucleus alongside neutrons. Its mass is about 1 u — roughly 1,836 times an electron's — so protons supply nearly all the atom's mass. The number of protons, called the atomic number, is the element's identity card: change it and you change the element itself. In a neutral atom, protons are balanced by an equal number of electrons.
For example
The nucleus of the simplest hydrogen atom is just one lone proton, with no neutron at all — remove it and nothing elemental remains.