'Tolerance' is Latin for 'bearing weight' — from PIE *telh- (to carry). Enduring what you find difficult.
The ability or willingness to tolerate something, especially opinions or behavior one does not necessarily agree with.
From Latin 'tolerantia' (endurance, the capacity to bear hardship), from 'tolerare' (to bear, endure, sustain, put up with), from PIE *telh₂- (to lift, support, bear a weight). The PIE root *telh₂- is productive and ancient: Latin 'tollere' (to lift, to raise — suppletive perfect of 'ferre'), Latin 'latus' (carried — suppletive participle of 'ferre'), Greek 'tlēnai' / 'tlaō' (to bear, endure), Greek 'Atlas' (the Titan condemned to bear the heavens — literally 'the Endurer'), and Sanskrit 'tulā' (scales, balance — that which bears weight equally). 'Tolerance' entered English via Old French 'tolerance' in the 15th century, initially with physical senses (a body's tolerance for heat or pain) before the decisive
'Tolerance,' 'atlas,' and 'extol' may all share PIE *telh₂- (to bear). Tolerance is bearing-with. Atlas bears the sky on his shoulders. To extol is to 'lift up' in praise. The same root connects enduring disagreement, holding up the heavens, and raising someone in praise — all forms of bearing weight.