What does preprocessing mean?
Preprocessing means preparing or transforming information before it passes through a main processing stage. It is especially common in computing and data science, where raw data may first be cleaned, filtered, normalised, encoded, or converted into a suitable format. For example, text preprocessing might remove irrelevant markup and standardise spelling before a language model analyses the text. The term can also apply to images, audio, sensor readings, and other forms of input. Although preprocessing is often routine and unglamorous, its results can strongly influence the accuracy and usefulness of later analysis. It should not be confused with processing in general: preprocessing specifically occupies the preparatory stage before the principal operation, while processing can refer to the whole process or only its main stage.
nounPreliminary processing or preparation of data, material, or other input before it undergoes a main or more extensive stage of processing. In computing, it commonly refers to transforming raw data into a cleaner or more useful form before analysis or model training.
- Preliminary processing or preparation carried out before a main or more extensive stage of processing, especially the cleaning and transformation of data before analysis, modelling, or use.
"The model performs automatic preprocessing of the text before analysing its sentiment."
"Image preprocessing removed noise and normalised the dimensions of each photograph."
"Careful preprocessing of the survey responses made the results easier to analyse."
Rare and non-standard in general use; preprocessing is normally treated as an uncountable noun.
"The report compares several separate preprocessings of the same dataset."
Data preprocessing is the unglamorous first step in which raw information is tidied, cleaned, and reshaped before the serious analysis begins.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does preprocessing come from?
Preprocessing is a compound formed in English from the prefix pre-, meaning “before,” and processing, the gerund of process. The prefix pre- comes through Old French from Latin prae, “before,” while process ultimately derives from Latin procedere, “to go forward.” The compound became established as a technical term as data processing and computer systems developed.
Related word forms
How preprocessing is actually used
This is primarily a technical term used in computing, data science, signal processing, and related fields. It is normally treated as an uncountable mass noun, and the spelling with a hyphen is common when it functions attributively.
Easily confused with preprocessing
Preprocessing occurs before a main operation, whereas processing refers to the main operation itself and may include both earlier preparatory steps and later stages.