In order to rename theme words, you can use Loco Translate plugin.
Please see below the steps that needs to be followed:
1.Install Loco Translate plugin
2. Go to Loco Translate – Manage translations
—select the theme and add New language
— select the language that you have chosen in Settings-General
— make sure that you select the exact language- Start translating
3. Search for the words that you wish to rename
— add the new words and save
