What is "eiusdem generis"?
Eiusdem (or ejusdem) generis means 'of the same type'. That is to say that if a general word follows two or more specific words, that general word will only apply to things of the same type as the specific words.
Give an example of eiusdem generis.
In Powell v. Kempton Park Racecourse Co.  AC 143 the House of Lords had to decide whether s. 1 of the Betting Act 1853, which prohibited the keeping of a 'house, office, room or other place' for the purpose of betting, applied to Tattersall's Ring, which was an outdoor area at the racecourse. The court said it did not, as the specific places were all indoors. However, if the words 'other place' had been followed by a word like 'wheresoever' or 'whatsoever', the rule would not apply. The rule is really a presumption, which can be displaced by a contrary intention shown in the legislation. In the example given, adding the words 'wheresoever' or 'whatsoever' would show that the words 'other place' should not be limited to places which were indoors.
What is "noscitur a sociis"?
Literally, this means 'known by the company it keeps'. That is to say that a word derives meaning from surrounding words. The eiusdem generis rule is used for general words, noscitur a sociis for specific words.
Give an example of noscitur a sociis.
In Pengelly v. Bell Punch Co. Ltd  1 WLR 1055 the court had to decide whether a floor used for storage came under the Factories Act 1961, whereby 'floors, steps, stairs, passageways and gangways' had to be kept free from obstruction. The court held that as all the other words were used to indicate passage, a floor used exclusively for storage did not fall within the Act.
What is "expressio unius est exclusio alterius"?
This means 'to express one is to exclude others'; therefore mention of one or more specific things may be taken to exclude others of the same type.
Give an example of expressio unius est exclusio alterius.
In R v. Inhabitants of Sedgley (1831) 2 B & Ald 65 the court held that the poor rate levied on occupiers of 'lands, houses and coal mines' under the Poor Relief Act 1601 could not be levied on owners of other types of mine.
This case is perfectly clear, as otherwise there was no explanation for the insertion of the word 'coal'. However, care must be taken when using this particular rule, as the omission may be inadvertent.
A more recent example of the use of this rule can be found in the case of R v. Secretary of State for the Home Department, ex parte Crew  IMM AR 94. Here, it was used to exclude the father of an illegitimate child from rights under the immigration law at the time, because the definitions section specifically mentioned the mother alone.