A word stem is the form of a word that can accept affixes (suffixes and prefixes) and is thus common to all inflected variants.

• linguistics
• reference

A root word is a word with no prefixes or suffixes, meaning that it is the primary lexical unit of a set of words and represents the principle semantic meaning of the set.

• linguistics
• reference

Lemmatization is the process of reducing a word to its lemma (canonical form). In natural language processing, a lemmatizer may be used to reduce all words in a given text to their lemmas, which makes comparative analysis possible based on canonical forms.

• gensim
• linguistics
• nlp
• nltk
• reference
• spacy

A rectified linear unit (ReLU) is an activation function that outputs the input directly if the input is positive, and otherwise outputs zero.

• deep learning
• neural networks
• reference

Back-propagation is an algorithm used during the training process of a feedforward neural network.

• deep learning
• neural networks
• reference

A feedforward neural network (aka multilayer perceptron or deep feedforward network) is a supervised learning network in which information only flows forward.

• deep learning
• neural networks
• reference

Loss functions are used to quantify to what extent a prediction was right/wrong (rather than simply if it was right or wrong.) The purpose of a loss function is to work as part of the optimization process to update a neural network so that it reaches the desired result.

• deep learning
• neural networks
• reference

Overfitting is a phenomenon in statistics and machine learning, wherein a model maximizes performance on training data to the extent that it is unsuitable for unseen data.

• machine learning
• reference
• statistics

An activation function is used to determine whether an input in a feedforward neural network is moved from one layer to the next.

• deep learning
• neural networks
• reference

A lemma is the canonical form of a word, also known as the dictionary form because it is often used as the primary entry in a dictionary.

• linguistics
• nlp
• reference