A vocabulary extension should do three things well:

Lookup: understand a word instantly without breaking flow.
Capture: save the word with enough context to make it memorable.
Retention: bring the word back later (spaced repetition) so it doesn't disappear.

Plenty of tools do the first part. Fewer do the second. Very few do the third well.

Below is a practical comparison of vocabulary-first extensions. Features change, so treat this as a 2026 snapshot.

[Screenshot Placeholder] Decision tree graphic: “lookup only” vs “save + review” vs “dedicated reading sessions”

Quick Comparison Table

Tool	Strength	Best For
WordHub	Retention-first workflow	Reading + saving + spaced repetition
Google Dictionary	Minimalist lookup	Fast definitions, no system
Readlang	Reading sessions	Import an article and read with click-to-translate
Toucan	Light immersion	Passive exposure during browsing
Mate Translate	Translation utility	Quick translations across sites

What Makes WordHub Different

WordHub is built around “words that stay.” It combines:

Fast lookup: hover + Alt+D / double-click.
Context saving: sentence + page info so review triggers memory.
Spaced repetition review: daily quiz that pulls words due for review.
Page Scan + Analysis: harvest difficult words after you read.
Reading Mode: clean long-form reading with translation support.

Which One Should You Choose?

You just want definitions: Google Dictionary.
You want dedicated reading sessions: Readlang.
You want vocabulary retention: WordHub.
You want passive exposure: Toucan (but pair it with a review tool).
You mainly need translation: a translation-focused extension like Mate Translate.

The best tool is the one that matches your behavior. If you read online every day, a retention-first workflow turns “normal browsing” into vocabulary progress almost automatically.