Use VLOOKUP when lookup values are located in the first column of a table with information organized vertically. Use HLOOKUP when lookup values are located in the first row of a table, and each record appears in a new column. Range_lookup controls whether value needs to match exactly or not.
senescence - the organic process of growing older and showing the effects of increasing age. ageing, aging. catabiosis - normal aging of cells. biological process, organic process - a process occurring in living organisms.
There's also the much rarer senectitude, which, like senescence, refers to the state of being old (specifically, to the final stage of the normal life span). senescent, from Latin senescent-, senescens, present participle of senescere to grow old, from sen-, senex old.