Tahini starts with sesame, not chickpeas
The idea
Tahini and hummus are different things. Tahini is a sesame paste used in sauces and dips; hummus has a chickpea base and commonly includes tahini as an ingredient. Knowing the difference helps when comparing a tahini sauce with a bowl of hummus or asking about ingredients.
A practical next step
Read the dish description before ordering a dip. Sesame matters to anyone avoiding that ingredient, even when the finished sauce looks pale and creamy.