preludial (?.)

• antecedent
• anterior
• chief
• exordial
• first
• foremost
• headmost
• inaugural
• inductive
• initiatory
• introductory
• leading
• precedent
• preceding
• precessional
• precursory
• prefatory
• prefixed
• prelim
• preliminary
• prelusive
• preparative
• preparatory
• prepositive
• prevenient
• prior
• proemial
• propaedeutic