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Azure AI-900 Glossary: Key Terms

Azure AI-900 glossary of AI concepts, vision, language, and generative AI terms.

Use this glossary when AI-900 terms start to blur together. Keep it next to the lessons and the cheat sheet, not in place of them.

High-value terms

Term Short meaning Fast exam anchor
AI workload the main kind of problem being solved classify the task before naming the service
classification predict a category label output
regression predict a number numeric output
clustering discover groups without labels unlabeled grouping
supervised learning train from labeled examples labels already exist
deep learning neural-network-based ML for complex patterns common in image, audio, and language tasks
transformer architecture model design used heavily in modern language and generative systems relevant to language and generative AI
feature input field used by a model what the model reads
label known target used to train supervised learning what the model learns to predict
training data examples used to fit the model learning stage
validation data held-out data used to check generalization reality check against memorization
overfitting model looks good on training data but weak on new data memorized instead of generalized
inference using a trained model or service on new input production or scoring stage
OCR extract text from images or documents read visual text
object detection identify objects and where they are what plus where
sentiment analysis detect tone in text positive, negative, neutral
entity recognition extract names, places, dates, organizations, or similar items pull structure from text
grounding provide trusted context to a generative model at runtime answer from supplied content
hallucination unsupported or fabricated output sounds plausible but wrong
model catalog collection of model choices in the Foundry platform surface compare available model options
responsible AI principles for trustworthy AI use fairness, safety, privacy, inclusiveness, transparency, accountability

Commonly confused pairs

Pair Keep this distinction clear
classification vs regression category vs number
classification vs clustering labeled prediction vs unlabeled grouping
training vs inference learning vs using
training data vs validation data fitting vs checking generalization
feature vs label input vs target
computer vision vs document processing general image interpretation vs document reading and structure extraction
NLP vs speech text-first workload vs audio-first workload
Azure AI Language vs Azure AI Speech text analysis vs spoken-language services
Azure Machine Learning vs prebuilt Azure AI services custom-model lifecycle vs ready-made AI capability
grounding vs fine-tuning runtime context vs changing model behavior through training
Azure AI Foundry vs Azure OpenAI Service broader generative-AI platform surface vs model-service access
fairness vs inclusiveness outcome bias vs usability across different users and conditions

If three terms blur together

If you keep mixing up… Use this anchor
Vision, document processing, and generative AI analyze images, extract existing document content, and create new content
classification, regression, and clustering category, number, and unlabeled grouping
training, validation, and inference learn, test generalization, and use
Language, Speech, and Machine Learning text analysis, audio processing, and predictive modeling
Azure AI Foundry, Azure OpenAI Service, and model catalog platform surface, model service, and model-selection shelf

One-sentence memory hooks

  • If the output is a category, think classification.
  • If the output is a number, think regression.
  • If there are no labels and the goal is grouping, think clustering.
  • If the clue starts with audio, think Speech before Language.
  • If the clue is about forms or invoices, think document processing before generic vision.
  • If the model must answer from enterprise content, think grounding.
  • If the question asks for custom model training and deployment, think Azure Machine Learning.

Best next surface by term family

If the term is really about… Revisit this page
workload choice and service fit Cheat Sheet
exam status, retirement, and naming changes FAQ
pacing and remediation sequence Study Plan
official Microsoft links and live scope Resources
Revised on Sunday, May 10, 2026