Question: I need a note-taking app that allows me to annotate and highlight text, and also provides definitions for key terms.

If you're looking for a note-taking app that lets you annotate and highlight text, and that offers definitions for important terms, genei is worth a look. It's got AI-based research and note-taking abilities that can automatically summarize articles, analyze them and extract information. You can annotate and highlight text, tag words and phrases with your own definitions, and extract keywords with their definitions. It's geared for professional writers, academics and researchers who want to get more out of their research and writing.

Another tool worth mentioning is Scholarcy, which is geared for academic papers. It can convert complex documents into interactive summary flashcards, summarize, analyze, organize and synthesize. Scholarcy also lets you take notes and highlight passages, so students and researchers can better understand complex information and manage their time better.

For a more general learning efficiency tool, check out NoteGPT. This AI-based knowledge management tool can help you summarize, take notes and organize information from articles, podcasts and YouTube videos. It can also generate AI flashcards, automatically take notes and collaborate with others, which makes it useful for students and professionals who need to quickly digest a lot of information.

Last, Glasp offers a web-based and PDF highlighting and note-taking interface. You can highlight and annotate web pages and PDFs, organize and tag your notes, and export them to common formats. Glasp also can generate AI summaries for web pages, PDFs and videos, which is useful for researchers and students who want to keep a record of their learning journey.