first appointment
first approach
first approximation
first arrival
first article
first assessment
first attack
first attempt
first author
first baby
first being
first biopsy

first birth
first birthday
first bite
first block
first branch
first branchial arch
first breeding
first capture
first case
first case report
first cell
first cell division
first century

first century ad
first century bc
first challenge
first characterization
first child
first choice
first choice therapy
first choice treatment
first class
first clear evidence
first cleavage
first clinical manifestation
first clutch

first cohort
first column
first committed step
first comparative study
first comparison
first complete remission
first component
first compound
first comprehensive study
first condition
first consultation
first contact
first contribution

first coordination shell
first coordination sphere
first country
first course
first crystal structure
first cycle
first data
first day