Answer:-

a. Nanoscience

Nanoscience is the study of phenomena and manipulation of materials at atomic, molecular, and macromolecular scales where properties differ significantly from those at a larger scale.

b. Nanotechnology

Nanotechnology is the design, characterization, production and application of structures, devices and systems by controlling shape and size at nanometer scale.
c. Nanomaterial

The nanomaterial is a material having structural components with at least one dimension in the nanometer scale, that is, 1-100 nm.
d. Nanochemistry

Nanochemistry is the combination of chemistry and nanoscience which deals with designing and synthesis of materials of nanoscale with different sizes and shape, structure and composition, and their organization into functional architectures.