What is lanthanoid and actonoid contradiction

In lanthanides there is a gradual increase in atomic size, atomic radii and ionic radii with increase in atomic number. This regular decrease is known as lanthanide contraction.
Causes:In lanthanides, the nuclear charge increases by one unit at each successive element and this new electron enters the 4f-subshell. Due to the peculiar shapes of f-orbitals, there is imperfect shielding of electrons from the nuclear attraction. As a result of this the size of lanthanide atoms decreases.
In actinoid there is a gradual increase in atomic size, atomic radii and ionic radii with increase in atomic number. This regular decrease is known as actinoid contraction. Causes:In actinoid, the nuclear charge increases by one unit at each successive element and this new electron enters the 5f-subshell. Due to the peculiar shapes of f-orbitals, there is imperfect shielding of electrons from the nuclear attraction. As a result of this the size of actinoids atoms decreases.