Cloning is the process of creating an identical copy of an original organism or thing.
A cloning in the biological sense, therefore, is a molecule, single cell (like bacteria, lymphocytes etc.) or multi-cellular organism that has been directly copied from and is therefore genetically identical to another living organism.
Sometimes this term can refer to "natural" clones made either when an organism is asexually reproduced by chance (as with identical twins), but in common parlance, a clone is an identical copy created intentionally.
Molecular cloning refers to the procedure of isolating a DNA sequence of interest and obtaining multiple copies of it in an organism.
Cloning is frequently employed to amplify DNA fragments containing genes, an essential step in their subsequent analysis.
Frequently, the term cloning is misleadingly used to refer to the identification of the chromosomal location of a gene associated with a particular phenotype of interest.
In practice, localisation of the gene does not always enable one to amplify the relevant genomic sequence.
Cloning of any DNA sequence involves the following four steps: amplification, ligation, transfection, and screening / selection.