What is meaning of Buddha and how he called Buddha?
Definition of Buddha based on Pali Dictionary is here:

Buddha Skt., Pali, lit., “awakened one.”

The Wikipedia entry is here:

The word Buddha means &quot;awakened one&quot; or &quot;the enlightened one&quot;.
Hypothetical root budh &quot;perceive&quot; 1. Pali buddha – &quot;understood, enlightened&quot;, masculine &quot;the Buddha&quot;; Aśokan (the language of the Inscriptions of Aśoka) Budhe nominative singular; Prakrit buddha – ‘ known, awakened ’; Waigalī būdāī, &quot;truth&quot;; Bashkarīk budh &quot;he heard&quot;; Tōrwālī būdo preterite of bū, &quot;to see, know&quot; from bṓdhati; Phalūṛa búddo preterite of buǰǰ , &quot;to understand&quot; from búdhyatē; Shina Gilgitī dialect budo, &quot;awake&quot;; Gurēsī dialect budyōnṷ intransitive &quot;to wake&quot;; Kashmiri bọ̆du, &quot;quick of understanding (especially of a child)&quot;; Sindhī ḇudho, past participle (passive) of ḇujhaṇu, &quot;to understand&quot; from búdhyatē, West Pahāṛī buddhā, preterite of bujṇā, &quot;to know&quot;; Sinhalese buj (j written for d), budu, bud, but, &quot;the Buddha&quot;.

Buddha means one who understood or awakened. This understanding / awakening is based on intelligence gained.