Culture is the decisions you make. Who you hire and promote. Who you let go. Who and what you reward. How decisions are made. What happens when something bad happens. What happens if you criticize your superior publicly. How much autonomy an employee has. How many requests do you have to fill to get post-its. What perks do you, or do you not, offer.
It means that mission fit and talent are the two things you care about, and that gender, nationality, race, social background, or disabilities are not hiring criteria.