'Tax' is Latin for 'to assess by touching' — from 'tangere.' The government's hand on your income.
A compulsory contribution to state revenue, levied by the government on workers' income, business profits, or added to the cost of some goods and services; to impose a tax on; to make heavy demands on.
From Old French 'taxer' (to tax, to assess, to charge), from Latin 'taxāre' (to evaluate, to assess, to touch sharply, to censure), an intensive or frequentative form of 'tangere' (to touch, to handle), from PIE *tag- (to touch, to handle). The semantic progression is compressed and telling: 'to touch' → 'to handle goods' → 'to assess their value by handling' → 'to rate or levy based on assessed value.' Roman tax collectors were known for literally touching goods
The word 'taxi' (short for 'taxicab') is also related to 'tax.' A taximeter — the device that calculates fares — gets its name from French 'taximètre,' from 'taxe' (a rate, charge, from the same Latin 'taxāre') + Greek 'metron' (measure). So a taxicab is literally a 'rate-measuring cab,' and the 'taxi' in 'taxicab' is etymologically the same word as the 'tax' you pay to the government.