One of the thousand and eight names of Śiva (Shiva). He is addressed as Sthira (Static), Sthāṇu (Sthanu, motionless), etc. because he is thought of as possessing the static, immovable form of Brahma. He is also famous as Acalopama based on the same idea of Brahma. Nīlakaṇṭha (Neelakantha), the annotator, while elucidating the meaning of acalopama, writes — acalopamo niścalastattvajñanītyarthaḥ.
He is the immovable form of absolute-Brahma, none of the mysteries of this universe are hidden or unknown to him— that is why he is known by the name of Acalopama.