On the basis of this icchA -- the first wish, as it may be called, and the Upanishad also says: ‘akAmayata’ - the kriyA-shakti (the power of Action) begins the pancha-kRtya-leelA. Thus, what was the paraBrahman by itself in itself, willed to ‘become’. It is for this divine will that the Upanishad uses the word ‘kAma’, meaning desire.
This ‘desire’ is not to be taken in any derogatory sense. It is pure Divine Will from Being to Becoming. Thus the first evolute from Brahman is this divine kAma. So the Shakti that is the origin of this is called KAmeshvari and the ShivaM in which this kAma sprouted is therefore called KAmeshwara.