The word 'Dev' has many meanings—
" देवो दानाद् वा , दीपनाद् वा , द्योतनाद् वा , द्युस्थानो भवतीति वा | " ~ (Nirukta - 7/15)
Accordingly, the sign of 'Dev' is 'charity'. Whoever gives his dear thing and life for the benefit of everyone, he is a Dev.
The word 'Koti' has two meanings - 'type' and 'crore'. There are thirty three types of gods in the world, that is thirty three types of gods, not thirty three crores. The Atharvaveda-10/28/27 states -
तान् वै त्रयास्त्रिंशद् देवानेके ब्रह्मविदो विदुः || "
The thirty three cosmic elements within his body are disposed as limbs and some learned men who knows about universe and it's master knows those thirty three cosmic powers.
(1) 8 Vasu — Earth, water, fire, air, sky, moon, sun and Nakshatra, these eight are called Vasu by being the abode of all. These eight Vasus are devas from giving shelter to all beings.
Five प्राण — प्राण , उदान , समान , व्यान और अपान।
Five उपप्राण — नाग , कूर्म , कृकल , देवदत्त और धनञ्जय।
"अन्नाद् भवन्ति भूतानि पर्जन्यादन्नसम्भवः|
यज्ञाद् भवति पर्जन्यो यज्ञः कर्म समुद् भवः||"
That means beings arise from food, grain from clouds and clouds from yajna.
(5) Vidhyut — विद्युत is a Dev, because it is a साधन of ऐश्वर्य. It gives the साधन of speed, power, light, prosperity and happiness.
According to बृहदारण्यक उपनिषद ३/१/६ — "कतम इन्द्रः ? अशनिरिति | "
विद्युत is the साधन of Lord Indra means "ऐश्वर्य".
In addition to the Atma, the remaining thirty-two devas are 'जड़' and are called devas of usage. They are always used for Chetan.
" परमेश्वर एवेष्टदेवोsस्ति " means that ईश्वर is the presiding deity of all human beings.
॥ तस्मै परमेश्वराय नम: ॥