Molecular fingerprint

«Molecular fingerprints are a way of encoding the structure of a molecule. The most common type of fingerprint is a series of binary digits (bits) that represent the presence or absence of particular substructures in the molecule. Comparing fingerprints allows you to determine the similarity between two molecules, to find matches to a query substructure, etc. [1]». «Fingerprints are a very abstract representation of certain structural features of a molecule [2]». «The similarity-based virtual screening (a kind of ligand-based virtual screening) assumes that all compounds in a database that are similar to a query compound have similar biological activity. (...). To achieve high efficacy of similarity-based screening of databases containing millions of compounds, molecular structures are usually represented by molecular screens (structural keys) or by fixed-size or variable-size molecular fingerprints. Molecular screens and fingerprints can contain both 2D- and 3D-information [3]». «Molecular fingerprints encode properties of small molecules and assess their similarities computationally through bit string comparisons. Based on the similarity to a biologically active template, molecular fingerprint methods allow for identifying additional compounds with a higher chance of displaying similar biological activities against the same target – a process commonly referred to as virtual screening [4]». It is «a unique pattern indicating the presence of a particular molecule, based on specialized analytic techniques such as mass- or x-ray-spectroscopy, used to identify a pollutant, drug, contaminant, or other chemical in a test sample [5].»
Example [6]:

 Bibliographic references:

[1] 1. Molecular fingerprints and similarity searching — Open Babel v2.3.1 documentation. Openbabel.org. https://openbabel.org/docs/dev/Fingerprints/intro.html. Published 2011. Accessed July 22, 2018.

[2] 2. Daylight Theory: Fingerprints. Daylight.com. http://www.daylight.com/dayhtml/doc/theory/theory.finger.html. Published 2007. Accessed July 22, 2018.

[3] Chemical similarity. En.wikipedia.org. https://en.wikipedia.org/wiki/Chemical_similarity. Published 2018. Accessed July 22, 2018.
[4] Muegge I, Mukherjee P. An overview of molecular fingerprint similarity search in virtual screening. Expert Opin Drug Discov. 2016;11(2):137-48. Available at: https://doi.org/10.1517/17460441.2016.1117070.
[5] Chemical fingerprint dictionary definition | chemical fingerprint defined. Yourdictionary.com. http://www.yourdictionary.com/chemical-fingerprint. Published 2018. Accessed July 22, 2018.
[6] Luo W, Chan KC. Discovering patterns in drug-protein interactions based on their fingerprints. BMC Bioinformatics. 2012 Jun 11;13 Suppl 9:S4. Available at: https://doi.org/10.1186/1471-2105-13-S9-S4.