Your exact workflow is not yet a standard feature in one mainstream app, but you can get very close with a vocabulary-management app that has a browser extension and built-in dictionary lookup, paired with a spaced-repetition review mode. The key is to check that the app works with Safari on iOS and desktop and lets you set two language patterns: native language to native definition, and foreign word to translation. If that exact combination does not exist, a simple fallback is to capture words into a notes file and import them into a flashcard tool that supports spaced repetition.
When evaluating apps, focus on five points. First, extension and share support: on iPhone, the app needs an iOS share extension so selected text from Safari can be sent to it; on desktop, it needs an extension for Safari or Edge. Many modern extension-based apps work in Edge because Edge supports Chrome extensions, but Safari support is less common, so test on your actual devices. Second, automatic lookup: the app should have a dictionary service where you can choose the source language and target language. For English to Dutch, this often works well. For Dutch to Dutch definitions, the quality depends on the dictionary source, so check whether you can edit the definition or add your own notes after it saves. Third, review settings: look for a daily target, new cards per day, and an SRS algorithm. Some apps show a review queue but do not schedule it; that is enough if you prefer manual control. Fourth, language pairs: make sure you can create different decks or fields for definition and translation so the same saved word can be reviewed in more than one way. Fifth, data export: choose a tool that lets you export your words, otherwise you can get locked into a platform that later changes.
Honest tradeoffs: automatic translation is never as accurate as a good human-made dictionary, and no tool will always choose the correct sense of a word. For Dutch, the translation direction is usually more reliable than the definition direction, especially for technical or regional words. Another limitation is that most vocabulary apps are designed primarily for foreign language learning, so "definition of a native word" may be made to fit into the same flashcard field as a translation. That is fine, because you can simply review with the prompt "what does this mean?" instead of "what is this in another language?"
To get started today, search your app store for "vocabulary builder" and "spaced repetition", then filter for apps that support Safari extensions. Read their privacy policy and reviews to see if they are actively maintained. Try the free version with a dozen words, including one Dutch definition and one English definition, and see how the auto-lookup behaves. If none are close enough, use a shortcut on your phone to append selected text to a note, and then import that note as a CSV into a flashcard program that lets you set your own review schedule. That gives you the same result with a little more manual work.