The Formal Conditional (εφόσον)

εφόσον is the FORMAL cousin of αν (“if”, Module 10). It means “provided that / as long as / inasmuch as / since” and, unlike a plain hypothetical αν, it treats the condition as GIVEN or already agreed - a fact you build on - so it takes the INDICATIVE, not a hypothetical form. «Εφόσον θέλεις, μπορείς να έρθεις» (as long as you want, you may come), «Θα σε βοηθήσω, εφόσον μπορώ» (I will help you, provided I can), «Εφόσον είναι έτοιμο το φαγητό, τρώμε» (since the food is ready, we eat). It shades between conditional (“as long as”) and causal (“given that / since”): the condition is presented as already true or accepted. Reach for εφόσον in formal or written registers; in everyday speech the plain αν of Module 10 still covers most ordinary conditions.