The Greek noun gala (G1051) means milk — both literal dairy milk and, metaphorically, elementary spiritual teaching. It appears in the New Testament in both senses: Paul uses it in 1 Corinthians 3:2 to describe basic Christian instruction suited to spiritual infants, and Peter in 1 Peter 2:2 uses it positively as "pure spiritual milk" to be eagerly desired.
The milk metaphor in the New Testament navigates a tension: milk is essential and good for infants (gala logikon — "rational/spiritual milk" in 1 Peter 2:2), yet prolonged reliance on milk when solid food is appropriate indicates spiritual immaturity (Hebrews 5:12-13). The trajectory of Christian growth is from milk to solid food — from basic gospel truths to mature theology. But the starting point — drinking deeply of Christ — is always essential.