*Brahman* / *Brahma* is frequently mentioned in the Upanishads as in the famous statement from Chandogya Upanishad 3.14.1: 

> 
> सर्वं खल्विदं ब्रह्म  
> 
> *sarvam khalvidam brahma*
>   
> All this is Brahman
> 
> 
> 

Is the term *Bhagavan* also mentioned in any Upanishad, and if so does it convey the same meaning as in Vishnu / Bhagavata Purana?