No not necessary, but we can say that when we talk about comparative we use "أكبر من" "bigger than"and when we about superlative we use only "أكبر" the biggest for example: Sasha is older than Mark ساشا "أكبر من" مارك I think that’s the biggest apple I’ve ever seen! أظن أن هذه هي "أكبر" تفاحة قد رأيتها

Hi Magdalena, Akbar is not plural, it's an adjective in comparison form = older/greater/bigger You can say also رجال كبار

we say: رجل كبير for singular and رجال كبار for plural concerning أكبر it means bigger or older according to the context and it's used to compare between two things for example: منزلي أكبر من منزلك my house is bigger than yours and الأكبر means the biggest or the oldest e.g أنا الأكبر بين أفراد عائلتي I'm the oldest in my family

رجال كبار old men رجل كبير old man الرجل الأكبر older or oldest man In Arabic adjective all are same in write and speak