def dictionary(parameter):
    """
    Nomenclatures for inputs and outputs, giving the descriptions, and the oilfield units

    Input:
    parameter = the input-output parameter, string

    Output:
    description = the description of the parameter
    unit = the oilfield unit of the parameter
    """
    description = {"Bg": "gas formation volume factor",
                   "Bo": "oil formation volume factor",
                   "Bw": "water formation volume factor",
                   "p": "pressure",
                   "temp": "temperature",
                   "cf":"formation compressibility",
                   "cw": "water compressibility",
                   "Efw": "formation expansion factor",
                   "Eg": "gas expansion factor",
                   "F": "reservoir voidage",
                   "Fr": "recovery factor",
                   "Gfgi": "initial gas in place",
                   "Gp": "cumulative gas produced",
                   "h": "thickness",
                   "Rv": "volatile oil-gas ratio",
                   "Rs": "solution gas-oil ratio",
                   "sw": "water saturation",
                   "t": "time",
                   "We": "water encroachment from aquifer",
                   "We_D": "dimensionless water encroachment from aquifer",
                   "Wp": "cumulative water produced",
                   "z": "gas compressibility factor",
                   "sg": "gas specific gravity",
                   "poro": "porosity",
                   "area": "reservoir productive area",
                   "Wi": "cumulative water injected",
                   "Gi": "cumulative gas injected",
                   "Vo": "condensate volume in PVT cell",
                   "z2": "two-phase compressibility factor",
                   "x_co2": "mole fraction of CO2 in gas",
                   "x_h2s": "mole fraction of H2S in gas",
                   "P_pr": "pseudo-reduced pressure",
                   "T_pr": "pseudo-reduced temperature"
                   }
    unit = {"Bg": "RB/scf",
            "Bo": "RB/STB",
            "Bw": "RB/STB",
            "p": "psia",
            "temp": "fahrenheit, celsius, rankine, kelvin",
            "cf": "psi^-1",
            "cw": "psi^-1",
            "Efw": "dimensionless",
            "Eg": "RB/scf",
            "F": "res bbl",
            "Fr": "dimensionless",
            "Gfgi": "ft3 (scf)",
            "Gp": "ft3 (scf)",
            "h": "ft",
            "Rv": "RB/scf",
            "Rs": "RB/STB",
            "swi": "fraction, v/v",
            "t": "any",
            "We": "res bbl",
            "We_D": "dimensionless",
            "Wp": "STB",
            "z": "dimensionless",
            "sg": "dimensionless",
            "poro": "fraction, v/v",
            "area": "ft2",
            "Wi": "STB",
            "Gi": "ft3 (scf)",
            "Vo": "res bbl",
            "z2": "dimensionless",
            "x_co2": "fraction, v/v",
            "x_h2s": "fraction, v/v",
            "P_pr": "dimensionless",
            "T_pr": "dimensionless"
            }

    description = description[parameter]
    unit = unit[parameter]

    return (description, unit)