What are the branches of chemistry and their definition?

The five major branches of chemistry are organic, inorganic, analytical, physical, and biochemistry. These divide into many sub-branches.
ORGANIC CHEMISTRY
Organic chemistry involves the study of the structure, properties, and preparation of chemical that consist primarily of carbon and hydrogen.
Organic chemistry overlaps with many areas including
Medicinal chemistry —the design, development, and synthesis of medicinal drugs. It overlaps with pharmacology (the study of drug action).
Organometallic chemistry — the study of chemical compounds containing bonds between carbon and a metal.
— the study of the chemistry of polymers.
Physical organic chemistry — the study of the interrelationships between structure and reactivity in organic molecules.
Stereochemistry — the study of the spatial arrangements of atoms in molecules and their effects on the of substances.
INORGANIC CHEMISTRY
Inorganic chemistry is the study of the properties and behaviour of inorganic compounds.
It covers all chemical compounds except organic compounds.
Inorganic chemists study things such as crystal structures, minerals, metals, catalysts, and most elements in .
Branches of inorganic chemistry include:

Bioinorganic chemistry — the study of the interaction of metal ions with living tissue, mainly through their direct effect on enzyme activity.

Geochemistry — the study of the chemical composition and changes in rocks, minerals, and atmosphere of the earth or a celestial body.

— the study of radioactive substances.

Organometallic chemistry — the study of chemical compounds containing bonds between carbon and a metal.

Solid-state chemistry — the study of the synthesis, structure, and properties of solid materials.

ANALYTICAL CHEMISTRY
Analytical chemistry involves the qualitative and quantitative determination of the chemical components of substances.
Examples of areas using analytical chemistry include:

Forensic chemistry — the application of chemical principles, techniques, and methods to the investigation of crime.

Environmental chemistry —the study of the chemical and biochemical phenomena that occur in the environment.It relies heavily on analytical chemistry and includes atmospheric, aquatic, and soil chemistry.

Bioanalytical Chemistry — the examination of biological materials such as blood, urine, hair, saliva, and sweat to detect the presence of specific drugs.

PHYSICAL CHEMISTRY
Physical Chemistry —the study of the effect of chemical structure on the physical properties of a substance.
Physical chemists typically study the rate of a chemical reaction, the interaction of molecules with radiation, and the calculation of structures and properties.
Sub-branches of physical chemistry include:

Photochemistry — the study of the chemical changes caused by light.

Surface chemistry — the study of chemical reactions at surfaces of substances. It includes topics like adsorption, heterogeneous catalysis, formation of colloids, corrosion, electrode processes, and chromatography.

Chemical kinetics — the study of the rates of chemical reactions, the factors affecting those rates, and the mechanism by which the reactions proceed.

Quantum chemistry — the mathematical description of the motion and interaction of subatomic particles. It incorporates quantization of energy, wave-particle duality, the uncertainty principle, and their relationship to chemical processes.

Spectroscopy — the use of the absorption, emission, or scattering of electromagnetic radiation by matter to study the matter or the chemical processes it undergoes.

BIOCHEMISTRY
Biochemistry is the study of chemical reactions that take place in living things. It tries to explain them in chemical terms.
Biochemical research includes cancer and stem cell biology, infectious disease, and cell membrane and structural biology.
It spans molecular biology, genetics, biochemical pharmacology, clinical biochemistry, and agricultural biochemistry.

Molecular biology — the study of the interactions between the various systems of a cell, such as the different types of DNA, RNA, and protein biosynthesis.

Genetics — the study of genes, heredity, and variation in living organisms.

Pharmacology — the study of mechanisms of drug action and the influence of drugs on an organism.
o Toxicology —a sub-branch of pharmacology that studies the effects of poisons on living organisms.

Clinical biochemistry — the study of the changes that disease causes in the chemical composition and biochemical processes of the body.

Agricultural biochemistry — the study of the chemistry that occurs in plants, animals, and microorganisms.

Thus, although there are FIVE main branches of chemistry, there are many sub-branches.
There is a huge overlap between Chemistry and Biology, Medicine, Physics, Geology, and many other disciplines.
Chemistry really is THE CENTRAL SCIENCE.