This is the 1995th most frequent Turkish word.
salı
Tuesday
Here, 'salı' is used as a noun representing a day of the week, specifically 'Tuesday.'
Salı günü tiyatroya gittik.
On Tuesday, we went to the theater.
In this usage, 'salı' is again a noun, but it is modified by 'her,' indicating a habitual action tied to Tuesdays.
Her salı çarşıdan alışveriş yapar.
Every Tuesday, she shops at the market.
In this sentence, 'salı' is part of a temporal expression, affirming the day of the week within a statement of disbelief.