RA, BP, EO, etc. Why different names for laws?

You probably notice that laws are called differently in the Philippines. This is especially confusing for freshmen in law school. Here are things you should know.

First of all, you must know that, under the present Constitution, "All existing laws, decrees, executive orders, proclamations, letters of instructions, and other executive issuances not inconsistent with this Constitution shall remain operative until amended, repealed, or revoked." (Article XVIII) This is the reason why our laws do not have uniform designations.

Philippine laws have had various nomenclature designations at different periods in the history of the Philippines, as shown below:

[1] Acts were laws promulgated by the Philippine government under United States sovereignty. These laws were from 1900 to 1935.

An example of this is Act 2031 or the Philippine Negotiable Instruments Law.

[2] Commonwealth Acts (or CAs) were those promulgated during the Philippine Commonwealth which was the administrative body that governed the Philippines from 1935 to 1946, aside from a period of exile in the Second World War from 1942 to 1945 when Japan occupied the country. It replaced the Insular Government, a United States territorial government, and was established by the Tydings–McDuffie Act. The Commonwealth was designed as a transitional administration in preparation for the country's full achievement of independence.

An example of this is CA 141 or the The Public Land Act.

[3] Republic Acts (or RAs) are presently those promulgated by the current Government of the Philippines under the 1987 Constitution. From 1946 to 1972, RAs were also used but stopped when the infamous 1973 Constitution was promulgated. (See Javellana v. Executive Secretary).

RA were restored in 1987 and have been used until today. An example of this is RA 9262 or the Anti-Violence against Women and their Children Act (VAWC Act).

[4] Presidential Decree (PDs) and Presidential Proclamation (PPs) were pieces of presidential issuance that had the force and effect of law when the Philippines was under President Ferdinant Marcos' martial law regime. These should not have been the case but were allowed under the so-called "constitutional tyranny" under the 1973 Constitution.
Note that "constitutional tyranny" means two or more government powers (either judicial, legislative or executive) exercised by only one person. (See Cruz on political law.)

An example of this is PD 442 or the Labor Code of the Philippines.

[5] Mga Batas Pambansa or BPs were laws promulgated by the infamous Batasang Pambansa (National Assembly) under the regime of Marcos.

BP 22 or the bouncing checks law is an example of this.

[6] Executive Orders or EOs were pieces of executive issuance by President Corazon Aquino during her provisional dictatorship prior to the ratification of the 1987 Constitution. These were issued by virtue of her powers under the Freedom Constitution.

An example of this is EO 209 or the Family Code of the Philippines.