Microsoft Office 365 synchronizes cloud dictionaries across devices

Microsoft Office 365 utilizes a cloud-based dictionary to synchronize user-added terms across multiple devices linked to the same Microsoft account. This synchronization applies to various applications, including Word, Outlook, Excel, and PowerPoint.

Users can manage these settings via the File/Options menu under Document Checking. In this menu, two distinct dictionary files are visible: ‘RoamingCustom.dic’, which serves as the synchronized cloud dictionary, and ‘CUSTOM.DIC’, which functions as the traditional local dictionary. Users can add unknown terms to the dictionary by right-clicking them when they are flagged by the spell checker.