Vocabulary.com is the rare educational site that actually understands how the human brain learns language. It ignores the 'flashcard' approach and focuses on exposure, forcing kids to understand a word's nuance across different contexts. It's essentially a digital version of the rich conversation and reading that builds literacy.

That said, it's still a screen-based drill. It's most effective when used as a targeted supplement—like mastering the vocab for The Giver before starting the first chapter—rather than a generic 'educational' way to kill time. If your kid is already a voracious reader, they might not need this; if they're struggling to bridge the gap between decoding and actually understanding what they read, this is a top-tier tool.