Table 2.

List of alternative terminologies used in Machine Learning to represent the same concept (our preferred choice is highlighted in italics). X denotes the input, Y or G the quantitative or qualitative output, respectively.

Synonims	Description
Quantitative or continuous variable	A variable assuming continuous values with explicit ordering
Qualitative, discrete, factor or categorical variable	A variable assuming discrete values with no explicit ordering
Observation or measurement	A realization of a statistical variable
Feature, predictor, attribute or independent variable j	The j-th column of the observed $X:{(x_{\mathit{ij}})}_{i=1}^N$
Output, outcome, response or dependent variable	The observed Y or G
Output class or output label i	The i-th element of the observed $G:g_i$
Data imputation	Replacing missing or inconsistent data with plausible data