DRDO: formed in 1958 from the Army's Technical Development Establishments, the DTDP and the Defence Science Organisation
Background
The Defence Research and Development Organisation (DRDO) functions under the Department of Defence Research and Development (DD R&D) of the Ministry of Defence.
DRDO was formed in 1958 from the amalgamation of the Technical Development Establishments (TDEs) of the Indian Army and the Directorate of Technical Development and Production (DTDP) with the Defence Science Organisation (DSO).
It was then a small organisation with 10 establishments or laboratories.
Its vision is to empower the nation with state-of-the-art indigenous defence and security technologies and systems.
Strategic systems and platforms developed include the Agni and Prithvi series of missiles, the light combat aircraft Tejas, the multi-barrel rocket launcher Pinaka and the air defence system Akash.
Its motto is "Balasya Mulam Vigyanam", which means the source of strength is science.
In plain words
DD R&D Department of Defence Research and Development — The department of the Ministry of Defence under which DRDO functions.
Pinaka Multi-barrel rocket launcher — A DRDO-developed multi-barrel rocket launcher named among its strategic systems.
Akash Air defence system — A DRDO-developed air defence system.