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.”