Concentration is to focus the mind on something
(Dharana: dha - to hold, carry, maintain)
Meditation is to reflect upon that which is being focused (the relationship between all constituent components)
(Dhyana: dhi - to reflect; yana - moving/going)
Samadhi is effortlessly flowing with that which was being focused on.
It’s the dissolution of the Self and becoming that which is being focused upon - to flow with the Divine through the Self, forgetting the limitations of the Self.
(Samadhi: Sama - equal; dha - to maintain ➡️ to maintain equality)
Concentration: I will stand on one foot
Meditation: how am I standing on one foot (what is my relationship to standing on one foot)
Samadhi: I am standing on one foot