We Hindus often hear the words "ishwar" and "bhagvan" . What are the differences between these two words?
Bhagvan is a term made of two different words, bhaga and van. Bhaga generally means supreme opulence. The Vishnu Purana defines bhaga as below:
aiśvaryasya samagrasya dharmasya yaśasariśrayaḥ
jñānavairāgyayoścaiva ṣaṇṇāṃ bhaga itīraṇā [VP - 6.5.74]
Complete splendor, virtue, glory, opulence, knowledge, dispassion - these six are known as bhaga.
So just like one who has dhana (wealth) is known as dhanavan, one how has all these six is known as bhagavan. ( bhaga + van = bhagavan ) But the opluences descried above are only found in the supreme personality of Godhead. Hence, the absolute truth, Brahman is also called as Bhagavan.
Apart from this, Bhagavan also means the omniscient being who has the complete knowledge of creation, dissolution, knowledge, ignorance, etc.:
utpattiṃ pralayaṃ caiva bhūtānāmāgatiṃ gatim
vettiṃ vidyāmavidyāṃ ca sa vācyo bhagavāniti [VP - 6.5.78]
Now, regarding Ishwara, it has been derived from the Sanskrit root ish, which means to rule. So Ishwara means the supreme being who rules over everyone and everything. But as God is only such being, He is also known as Ishwara. ( īśate iti īśvaraḥ )
So irrespective of whether we say Bhagavan or Iswara, both imply the same personal form of God. Just their meanings are different.
In Hindu Religion, the word Bhagwan has symbolic meaning too. The word encompasses Earth, Water, Fire, Air and Space – the five elements. Thus the term Bhagavan translates as the manifestation of the physical form of universe.
In the word भगवान (Bhagavan) –
‘भ’ stands for Bhoomi or Earth
'ग' stands for Gagan or Space
‘व’ stands for Vayu or Air
‘आ’ stands for Agni or Fire
‘न’ stands for Neer or Water