Allah is the One (Who is One “al-Wahid”), i.e., the One who does not have a partner with Him in Godhood, and no one deserves to be worshipped other than Him. Allah said in Surat Al-Baqarah verse #163:

﴿وَإِلهُكُمْ إِلَهٌ وَاحِدٌ﴾ سورة البقرة

This verse means: [Your God is one – without a partner].

Imam Abu Hanifah said in ‘Al-Fiqh al-’Akbar’: “Allah is One not in the terms of numbers, but in terms of not having any partner.”