楼梯 (lóutī) is a noun meaning "stairs," "staircase," or "stairway." It refers to a set of steps connecting different levels of a building. It can describe both indoor staircases and outdoor steps.
小心楼梯,这里有点滑。
Xiǎoxīn lóutī, zhèlǐ yǒudiǎn huá.
Be careful on the stairs; it's a bit slippery here.
他每天爬楼梯上班,当作锻炼身体。
Tā měitiān pá lóutī shàngbān, dàngzuò duànliàn shēntǐ.
He climbs the stairs to work every day as exercise.
沿着这个楼梯往上走就能到天台。
Yánzhe zhège lóutī wǎng shàng zǒu jiù néng dào tiāntái.
Go up along this staircase and you'll reach the rooftop.