What does this Hadith Mean: "The Qur'an was collected in the lifetime of the Prophet (ﷺ) by four..."

In this Hadith which is found in Bukhari and Muslim it says: >Anas Ibn Maalik said, "The Qur'an was collected in the lifetime of the Prophet (ﷺ) by four (men), all of whom were from the Ansar: Ubai, Mu`adh bin Jabal, Abu Zaid and Zaid bin Thabit.
**[ [Sunnah Ref: Bukhari 3810](https://sunnah.com/bukhari:3810) ]**
**[ [Sunnah Ref: Muslim 2465a](https://sunnah.com/muslim:2465a) ]** And I want to know what "collected" means here. Does it mean these four men compiled a physical mushaf or does it mean they memorised the Qur'an?